diff --git a/CMakeLists.txt b/CMakeLists.txt
index ee0810295..c9a01daed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -304,7 +304,10 @@ endif()
 # library. If not building a shared library ``-fPIC`` isn't needed and would add
 # unnecessary overhead.
 if (BUILD_LIBZ3_SHARED)
-  if (NOT MSVC)
+  # Avoid adding -fPIC compiler switch if we compile with MSVC (which does not
+  # support the flag) or if we target Windows, which generally does not use
+  # position independent code for native code shared libraries (DLLs).
+  if (NOT (MSVC OR MINGW OR WIN32))
     z3_add_cxx_flag("-fPIC" REQUIRED)
   endif()
 endif()
@@ -387,4 +390,3 @@ option(ENABLE_EXAMPLE_TARGETS "Build Z3 api examples" ON)
 if (ENABLE_EXAMPLE_TARGETS)
   add_subdirectory(examples)
 endif()
-
diff --git a/README.md b/README.md
index 3985fad27..502b32147 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,16 @@ CXX=clang++ CC=clang python scripts/mk_make.py
 
 Note that Clang < 3.7 does not support OpenMP.
 
+You can also build Z3 for Windows using Cygwin and the Mingw-w64 cross-compiler.
+To configure that case correctly, make sure to use Cygwin's own python and not
+some Windows installation of Python.
+
+For a 64 bit build (from Cygwin64), configure Z3's sources with
+```bash
+CXX=x86_64-w64-mingw32-g++ CC=x86_64-w64-mingw32-gcc AR=x86_64-w64-mingw32-ar python scripts/mk_make.py
+```
+A 32 bit build should work similarly (but is untested); the same is true for 32/64 bit builds from within Cygwin32.
+
 By default, it will install z3 executable at ``PREFIX/bin``, libraries at
 ``PREFIX/lib``, and include files at ``PREFIX/include``, where ``PREFIX``
 installation prefix if inferred by the ``mk_make.py`` script. It is usually
diff --git a/examples/java/JavaExample.java b/examples/java/JavaExample.java
index 74e94617d..5c8a7508f 100644
--- a/examples/java/JavaExample.java
+++ b/examples/java/JavaExample.java
@@ -188,7 +188,7 @@ class JavaExample
             /* do something with the context */
 
             /* be kind to dispose manually and not wait for the GC. */
-            ctx.dispose();
+            ctx.close();
         }
     }
 
diff --git a/examples/python/mus/marco.py b/examples/python/mus/marco.py
new file mode 100644
index 000000000..b6689636d
--- /dev/null
+++ b/examples/python/mus/marco.py
@@ -0,0 +1,185 @@
+############################################
+# Copyright (c) 2016 Microsoft Corporation
+# 
+# Basic core and correction set enumeration.
+#
+# Author: Nikolaj Bjorner (nbjorner)
+############################################
+
+"""
+Enumeration of Minimal Unsatisfiable Cores and Maximal Satisfying Subsets
+This tutorial illustrates how to use Z3 for extracting all minimal unsatisfiable
+cores together with all maximal satisfying subsets. 
+
+Origin
+The algorithm that we describe next represents the essence of the core extraction
+procedure by Liffiton and Malik and independently by Previti and Marques-Silva: 
+ Enumerating Infeasibility: Finding Multiple MUSes Quickly
+ Mark H. Liffiton and Ammar Malik
+ in Proc. 10th International Conference on Integration of Artificial Intelligence (AI)
+ and Operations Research (OR) techniques in Constraint Programming (CPAIOR-2013), 160-175, May 2013. 
+
+Partial MUS Enumeration
+ Alessandro Previti, Joao Marques-Silva in Proc. AAAI-2013 July 2013 
+
+Z3py Features
+
+This implementation contains no tuning. It was contributed by Mark Liffiton and it is
+a simplification of one of the versions available from his Marco Polo Web site.
+It illustrates the following features of Z3's Python-based API:
+   1. Using assumptions to track unsatisfiable cores. 
+   2. Using multiple solvers and passing constraints between them. 
+   3. Calling the C-based API from Python. Not all API functions are supported over the
+      Python wrappers. This example shows how to get a unique integer identifier of an AST,
+      which can be used as a key in a hash-table. 
+
+Idea of the Algorithm
+The main idea of the algorithm is to maintain two logical contexts and exchange information
+between them:
+
+    1. The MapSolver is used to enumerate sets of clauses that are not already
+       supersets of an existing unsatisfiable core and not already a subset of a maximal satisfying
+       assignment. The MapSolver uses one unique atomic predicate per soft clause, so it enumerates
+       sets of atomic predicates. For each minimal unsatisfiable core, say, represented by predicates
+       p1, p2, p5, the MapSolver contains the clause  !p1 | !p2 | !p5. For each maximal satisfiable
+       subset, say, represented by predicats p2, p3, p5, the MapSolver contains a clause corresponding
+       to the disjunction of all literals not in the maximal satisfiable subset, p1 | p4 | p6. 
+    2. The SubsetSolver contains a set of soft clauses (clauses with the unique indicator atom occurring negated).
+       The MapSolver feeds it a set of clauses (the indicator atoms). Recall that these are not already a superset
+       of an existing minimal unsatisfiable core, or a subset of a maximal satisfying assignment. If asserting
+       these atoms makes the SubsetSolver context infeasible, then it finds a minimal unsatisfiable subset
+       corresponding to these atoms. If asserting the atoms is consistent with the SubsetSolver, then it
+       extends this set of atoms maximally to a satisfying set. 
+"""
+
+from z3 import *
+
+def main():
+    x, y = Reals('x y')
+    constraints = [x > 2, x < 1, x < 0, Or(x + y > 0, y < 0), Or(y >= 0, x >= 0), Or(y < 0, x < 0), Or(y > 0, x < 0)]
+    csolver = SubsetSolver(constraints)
+    msolver = MapSolver(n=csolver.n)
+    for orig, lits in enumerate_sets(csolver, msolver):
+        output = "%s %s" % (orig, lits)
+        print(output)
+
+
+def get_id(x):
+    return Z3_get_ast_id(x.ctx.ref(),x.as_ast())
+
+
+class SubsetSolver:
+   constraints = []
+   n = 0
+   s = Solver()
+   varcache = {}
+   idcache = {}
+
+   def __init__(self, constraints):
+       self.constraints = constraints
+       self.n = len(constraints)
+       for i in range(self.n):
+           self.s.add(Implies(self.c_var(i), constraints[i]))
+
+   def c_var(self, i):
+       if i not in self.varcache:
+          v = Bool(str(self.constraints[abs(i)]))
+          self.idcache[get_id(v)] = abs(i)
+          if i >= 0:
+             self.varcache[i] = v
+          else:
+             self.varcache[i] = Not(v)
+       return self.varcache[i]
+
+   def check_subset(self, seed):
+       assumptions = self.to_c_lits(seed)
+       return (self.s.check(assumptions) == sat)
+        
+   def to_c_lits(self, seed):
+       return [self.c_var(i) for i in seed]
+
+   def complement(self, aset):
+       return set(range(self.n)).difference(aset)
+
+   def seed_from_core(self):
+       core = self.s.unsat_core()
+       return [self.idcache[get_id(x)] for x in core]
+
+   def shrink(self, seed):
+       current = set(seed)
+       for i in seed:
+          if i not in current:
+             continue
+          current.remove(i)
+          if not self.check_subset(current):
+             current = set(self.seed_from_core())
+          else:
+             current.add(i)
+       return current
+
+   def grow(self, seed):
+       current = seed
+       for i in self.complement(current):
+           current.append(i)
+           if not self.check_subset(current):
+              current.pop()
+       return current
+
+
+
+class MapSolver:
+   def __init__(self, n):
+       """Initialization.
+             Args:
+            n: The number of constraints to map.
+       """
+       self.solver = Solver()
+       self.n = n
+       self.all_n = set(range(n))  # used in complement fairly frequently
+
+   def next_seed(self):
+       """Get the seed from the current model, if there is one.
+            Returns:
+            A seed as an array of 0-based constraint indexes.
+       """
+       if self.solver.check() == unsat:
+            return None
+       seed = self.all_n.copy()  # default to all True for "high bias"
+       model = self.solver.model()
+       for x in model:
+           if is_false(model[x]):
+              seed.remove(int(x.name()))
+       return list(seed)
+
+   def complement(self, aset):
+       """Return the complement of a given set w.r.t. the set of mapped constraints."""
+       return self.all_n.difference(aset)
+
+   def block_down(self, frompoint):
+       """Block down from a given set."""
+       comp = self.complement(frompoint)
+       self.solver.add( Or( [Bool(str(i)) for i in comp] ) )
+
+   def block_up(self, frompoint):
+       """Block up from a given set."""
+       self.solver.add( Or( [Not(Bool(str(i))) for i in frompoint] ) )
+    
+
+
+def enumerate_sets(csolver, map):
+    """Basic MUS/MCS enumeration, as a simple example."""
+    while True:
+        seed = map.next_seed()
+        if seed is None:
+           return
+        if csolver.check_subset(seed):
+           MSS = csolver.grow(seed)
+           yield ("MSS", csolver.to_c_lits(MSS))
+           map.block_down(MSS)
+        else:
+           MUS = csolver.shrink(seed)
+           yield ("MUS", csolver.to_c_lits(MUS))
+           map.block_up(MUS)
+
+main()
+
diff --git a/scripts/mk_util.py b/scripts/mk_util.py
index b02e6e2b7..8fafd1caa 100644
--- a/scripts/mk_util.py
+++ b/scripts/mk_util.py
@@ -70,6 +70,7 @@ IS_OSX=False
 IS_FREEBSD=False
 IS_OPENBSD=False
 IS_CYGWIN=False
+IS_CYGWIN_MINGW=False
 VERBOSE=True
 DEBUG_MODE=False
 SHOW_CPPS = True
@@ -143,6 +144,9 @@ def is_osx():
 def is_cygwin():
     return IS_CYGWIN
 
+def is_cygwin_mingw():
+    return IS_CYGWIN_MINGW
+
 def norm_path(p):
     # We use '/' on mk_project for convenience
     return os.path.join(*(p.split('/')))
@@ -219,7 +223,10 @@ def rmf(fname):
 
 def exec_compiler_cmd(cmd):
     r = exec_cmd(cmd)
-    rmf('a.out')
+    if is_windows() or is_cygwin_mingw():
+        rmf('a.exe')
+    else:
+        rmf('a.out')
     return r
 
 def test_cxx_compiler(cc):
@@ -597,6 +604,8 @@ elif os.name == 'posix':
         IS_OPENBSD=True
     elif os.uname()[0][:6] == 'CYGWIN':
         IS_CYGWIN=True
+        if (CC != None and "mingw" in CC):
+            IS_CYGWIN_MINGW=True
 
 def display_help(exit_code):
     print("mk_make.py: Z3 Makefile generator\n")
@@ -1821,7 +1830,7 @@ class MLComponent(Component):
                 CP_CMD='copy'
 
             OCAML_FLAGS = ''
-            if DEBUG_MODE:             
+            if DEBUG_MODE:
                 OCAML_FLAGS += '-g'
             OCAMLCF = OCAMLC + ' ' + OCAML_FLAGS
             OCAMLOPTF = OCAMLOPT + ' ' + OCAML_FLAGS
@@ -1875,12 +1884,15 @@ class MLComponent(Component):
 
 
             OCAMLMKLIB = 'ocamlmklib'
-            LIBZ3 = '-L. -lz3'
-            if is_cygwin():
-                # Some ocamlmklib's don't like -g; observed on cygwin, but may be others as well.
+
+            LIBZ3 = '-L. -lz3'           
+            if is_cygwin() and not(is_cygwin_mingw()):
                 LIBZ3 = 'libz3.dll'
-            elif DEBUG_MODE:
+
+            if DEBUG_MODE and not(is_cygwin()):
+                # Some ocamlmklib's don't like -g; observed on cygwin, but may be others as well.
                 OCAMLMKLIB += ' -g'
+
             z3mls = os.path.join(self.sub_dir, 'z3ml')
             out.write('%s.cma: %s %s %s\n' % (z3mls, cmos, stubso, z3dllso))
             out.write('\t%s -o %s -I %s %s %s %s\n' % (OCAMLMKLIB, z3mls, self.sub_dir, stubso, cmos, LIBZ3))
@@ -1943,7 +1955,7 @@ class MLComponent(Component):
             out.write(' %s' % ((os.path.join(self.sub_dir, 'z3ml.cmxa'))))
             out.write(' %s' % ((os.path.join(self.sub_dir, 'z3ml.cmxs'))))
             out.write(' %s' % ((os.path.join(self.sub_dir, 'dllz3ml'))))
-            if IS_WINDOWS:
+            if is_windows() or is_cygwin_mingw():
                 out.write('.dll')
             else:
                 out.write('.so') # .so also on OSX!
@@ -2382,6 +2394,12 @@ def mk_config():
             CPPFLAGS     = '%s -DNDEBUG -D_EXTERNAL_RELEASE' % CPPFLAGS
         if TRACE or DEBUG_MODE:
             CPPFLAGS     = '%s -D_TRACE' % CPPFLAGS
+        if is_cygwin_mingw():
+            # when cross-compiling with MinGW, we need to statically link its standard libraries
+            # and to make it create an import library.
+            SLIBEXTRAFLAGS = '%s -static-libgcc -static-libstdc++ -Wl,--out-implib,libz3.dll.a' % SLIBEXTRAFLAGS
+            LDFLAGS = '%s -static-libgcc -static-libstdc++' % LDFLAGS
+                        
         config.write('PREFIX=%s\n' % PREFIX)
         config.write('CC=%s\n' % CC)
         config.write('CXX=%s\n' % CXX)
@@ -2411,6 +2429,8 @@ def mk_config():
             print('Host platform:  %s' % sysname)
             print('C++ Compiler:   %s' % CXX)
             print('C Compiler  :   %s' % CC)
+            if is_cygwin_mingw():
+                print('MinGW32 cross:  %s' % (is_cygwin_mingw()))
             print('Archive Tool:   %s' % AR)
             print('Arithmetic:     %s' % ARITH)
             print('OpenMP:         %s' % HAS_OMP)
diff --git a/scripts/update_api.py b/scripts/update_api.py
index a06f1fbb1..733d5b1fa 100755
--- a/scripts/update_api.py
+++ b/scripts/update_api.py
@@ -1324,36 +1324,80 @@ def mk_z3native_stubs_c(ml_dir): # C interface
         if len(ap) > 0:
             ml_wrapper.write('  unsigned _i;\n')
 
-        # declare locals, preprocess arrays, strings, in/out arguments
-        have_context = False
+        # determine if the function has a context as parameter.
+        have_context = (len(params) > 0) and (param_type(params[0]) == CONTEXT)
+
+        if have_context and name not in Unwrapped:
+            ml_wrapper.write('  Z3_error_code ec;\n')
+
+        if result != VOID:
+            ts = type2str(result)
+            if ml_has_plus_type(ts):
+                pts = ml_plus_type(ts)
+                ml_wrapper.write('  %s z3rv_m;\n' % ts)
+                ml_wrapper.write('  %s z3rv;\n' % pts)
+            else:
+                ml_wrapper.write('  %s z3rv;\n' % ts)
+
+        # declare all required local variables
+        # To comply with C89, we need to first declare the variables and initialize them
+        # only afterwards.
         i = 0
         for param in params:
             if param_type(param) == CONTEXT and i == 0:
-                ml_wrapper.write('  Z3_context_plus ctx_p = *(Z3_context_plus*) Data_custom_val(a' + str(i) + ');\n')
-                ml_wrapper.write('  Z3_context _a0 = ctx_p->ctx;\n')
-                have_context = True
+                ml_wrapper.write('  Z3_context_plus ctx_p;\n')
+                ml_wrapper.write('  Z3_context _a0;\n')
             else:
                 k = param_kind(param)
                 if k == OUT_ARRAY:
-                    ml_wrapper.write('  %s * _a%s = (%s*) malloc(sizeof(%s) * (_a%s));\n' % (
-                        type2str(param_type(param)),
+                    ml_wrapper.write('  %s * _a%s;\n' % (type2str(param_type(param)), i))
+                elif k == OUT_MANAGED_ARRAY:
+                    ml_wrapper.write('  %s * _a%s;\n' % (type2str(param_type(param)), i))
+                elif k == IN_ARRAY or k == INOUT_ARRAY:
+                    t = param_type(param)
+                    ts = type2str(t)
+                    ml_wrapper.write('  %s * _a%s;\n' % (ts, i))
+                elif k == IN:
+                    t = param_type(param)
+                    ml_wrapper.write('  %s _a%s;\n' % (type2str(t), i))
+                elif k == OUT or k == INOUT:
+                    t = param_type(param)
+                    ml_wrapper.write('  %s _a%s;\n' % (type2str(t), i))
+                    ts = type2str(t)
+                    if ml_has_plus_type(ts):
+                        pts = ml_plus_type(ts)
+                        ml_wrapper.write('  %s _a%dp;\n' % (pts, i))
+            i = i + 1
+
+
+        # End of variable declarations in outermost block:
+        # To comply with C89, no variable declarations may occur in the outermost block
+        # from that point onwards (breaks builds with at least VC 2012 and prior)
+        ml_wrapper.write('\n')
+
+        # Declare locals, preprocess arrays, strings, in/out arguments
+        i = 0
+        for param in params:
+            if param_type(param) == CONTEXT and i == 0:
+                ml_wrapper.write('  ctx_p = *(Z3_context_plus*) Data_custom_val(a' + str(i) + ');\n')
+                ml_wrapper.write('  _a0 = ctx_p->ctx;\n')
+            else:
+                k = param_kind(param)
+                if k == OUT_ARRAY:
+                    ml_wrapper.write('  _a%s = (%s*) malloc(sizeof(%s) * (_a%s));\n' % (
                         i,
                         type2str(param_type(param)),
                         type2str(param_type(param)),
                         param_array_capacity_pos(param)))
                 elif k == OUT_MANAGED_ARRAY:
-                    ml_wrapper.write('  %s * _a%s = 0;\n' % (type2str(param_type(param)), i))
+                    ml_wrapper.write('  _a%s = 0;\n' % i)
                 elif k == IN_ARRAY or k == INOUT_ARRAY:
                     t = param_type(param)
                     ts = type2str(t)
-                    ml_wrapper.write('  %s * _a%s = (%s*) malloc(sizeof(%s) * _a%s);\n' % (ts, i, ts, ts, param_array_capacity_pos(param)))
+                    ml_wrapper.write('  _a%s = (%s*) malloc(sizeof(%s) * _a%s);\n' % (i, ts, ts, param_array_capacity_pos(param)))
                 elif k == IN:
                     t = param_type(param)
-                    ml_wrapper.write('  %s _a%s = %s;\n' % (type2str(t), i, ml_unwrap(t, type2str(t), 'a' + str(i))))
-                elif k == OUT:
-                    ml_wrapper.write('  %s _a%s;\n' % (type2str(param_type(param)), i))
-                elif k == INOUT:
-                    ml_wrapper.write('  %s _a%s = a%s;\n' % (type2str(param_type(param)), i, i))
+                    ml_wrapper.write('  _a%s = %s;\n' % (i, ml_unwrap(t, type2str(t), 'a' + str(i))))
             i = i + 1
 
         i = 0
@@ -1375,9 +1419,9 @@ def mk_z3native_stubs_c(ml_dir): # C interface
         if result != VOID:
             ts = type2str(result)
             if ml_has_plus_type(ts):
-                ml_wrapper.write('%s z3rv_m = ' % ts)
+                ml_wrapper.write('z3rv_m = ')
             else:
-                ml_wrapper.write('%s z3rv = ' % ts)
+                ml_wrapper.write('z3rv = ')
 
         # invoke procedure
         ml_wrapper.write('%s(' % name)
@@ -1397,8 +1441,8 @@ def mk_z3native_stubs_c(ml_dir): # C interface
         ml_wrapper.write(');\n')
 
         if have_context and name not in Unwrapped:
-            ml_wrapper.write('  int ec = Z3_get_error_code(ctx_p->ctx);\n')
-            ml_wrapper.write('  if (ec != 0) {\n')
+            ml_wrapper.write('  ec = Z3_get_error_code(ctx_p->ctx);\n')
+            ml_wrapper.write('  if (ec != Z3_OK) {\n')
             ml_wrapper.write('    const char * msg = Z3_get_error_msg(ctx_p->ctx, ec);\n')
             ml_wrapper.write('    caml_raise_with_string(*caml_named_value("Z3EXCEPTION"), msg);\n')
             ml_wrapper.write('  }\n')
@@ -1408,9 +1452,9 @@ def mk_z3native_stubs_c(ml_dir): # C interface
             if ml_has_plus_type(ts):
                 pts = ml_plus_type(ts)
                 if name in NULLWrapped:
-                    ml_wrapper.write('  %s z3rv = %s_mk(z3rv_m);\n' % (pts, pts))
+                    ml_wrapper.write('  z3rv = %s_mk(z3rv_m);\n' % pts)
                 else:
-                    ml_wrapper.write('  %s z3rv = %s_mk(ctx_p, (%s) z3rv_m);\n' % (pts, pts, ml_minus_type(ts)))
+                    ml_wrapper.write('  z3rv = %s_mk(ctx_p, (%s) z3rv_m);\n' % (pts, ml_minus_type(ts)))
 
         # convert output params
         if len(op) > 0:
@@ -1450,7 +1494,7 @@ def mk_z3native_stubs_c(ml_dir): # C interface
                 elif is_out_param(p):
                     if ml_has_plus_type(ts):
                         pts = ml_plus_type(ts)
-                        ml_wrapper.write('  %s _a%dp = %s_mk(ctx_p, (%s) _a%d);\n' % (pts, i, pts, ml_minus_type(ts), i))
+                        ml_wrapper.write('  _a%dp = %s_mk(ctx_p, (%s) _a%d);\n' % (i, pts, ml_minus_type(ts), i))
                         ml_wrapper.write('  %s\n' % ml_alloc_and_store(pt, '_a%d_val' % i, '_a%dp' % i))
                     else:
                         ml_wrapper.write('  %s\n' % ml_alloc_and_store(pt, '_a%d_val' % i, '_a%d' % i))
diff --git a/src/api/java/AST.java b/src/api/java/AST.java
index e84dc8c81..e1cde837f 100644
--- a/src/api/java/AST.java
+++ b/src/api/java/AST.java
@@ -175,15 +175,8 @@ public class AST extends Z3Object implements Comparable<AST>
      * A string representation of the AST.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.astToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.astToString(getContext().nCtx(), getNativeObject());
     }
 
     /**
@@ -194,34 +187,18 @@ public class AST extends Z3Object implements Comparable<AST>
         return Native.astToString(getContext().nCtx(), getNativeObject());
     }
 
-    AST(Context ctx)
-    {
-        super(ctx);
-    }
-
-    AST(Context ctx, long obj)
-    {
+    AST(Context ctx, long obj) {
         super(ctx, obj);
     }
 
     @Override
-    void incRef(long o)
-    {
-        // Console.WriteLine("AST IncRef()");
-        if (getContext() == null || o == 0)
-            return;
-        getContext().getASTDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.incRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        // Console.WriteLine("AST DecRef()");
-        if (getContext() == null || o == 0)
-            return;
-        getContext().getASTDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getASTDRQ().storeReference(getContext(), this);
     }
 
     static AST create(Context ctx, long obj)
diff --git a/src/api/java/ASTDecRefQueue.java b/src/api/java/ASTDecRefQueue.java
index 32f6a5d0e..b0a6fa217 100644
--- a/src/api/java/ASTDecRefQueue.java
+++ b/src/api/java/ASTDecRefQueue.java
@@ -17,39 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class ASTDecRefQueue extends IDecRefQueue
+class ASTDecRefQueue extends IDecRefQueue<AST>
 {
     public ASTDecRefQueue() 
     {
         super();
     }
 
-    public ASTDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.incRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.decRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.decRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/ASTMap.java b/src/api/java/ASTMap.java
index 7bc485bf5..916811cec 100644
--- a/src/api/java/ASTMap.java
+++ b/src/api/java/ASTMap.java
@@ -20,8 +20,7 @@ package com.microsoft.z3;
 /**
  * Map from AST to AST
  **/
-class ASTMap extends Z3Object
-{
+class ASTMap extends Z3Object {
     /**
      * Checks whether the map contains the key {@code k}. 
      * @param k An AST
@@ -104,13 +103,7 @@ class ASTMap extends Z3Object
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.astMapToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.astMapToString(getContext().nCtx(), getNativeObject());
     }
 
     ASTMap(Context ctx, long obj)
@@ -124,16 +117,12 @@ class ASTMap extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getASTMapDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.astMapIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getASTMapDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getASTMapDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ASTVector.java b/src/api/java/ASTVector.java
index ab99e2aee..4d9ab291a 100644
--- a/src/api/java/ASTVector.java
+++ b/src/api/java/ASTVector.java
@@ -20,8 +20,7 @@ package com.microsoft.z3;
 /**
  * Vectors of ASTs.
  **/
-public class ASTVector extends Z3Object
-{
+public class ASTVector extends Z3Object {
     /**
      * The size of the vector
      **/
@@ -88,15 +87,8 @@ public class ASTVector extends Z3Object
      * Retrieves a string representation of the vector.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.astVectorToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.astVectorToString(getContext().nCtx(), getNativeObject());
     }
 
     ASTVector(Context ctx, long obj)
@@ -110,19 +102,15 @@ public class ASTVector extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getASTVectorDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.astVectorIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getASTVectorDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getASTVectorDRQ().storeReference(getContext(), this);
     }
-    
+
     /**
      * Translates the AST vector into an AST[]
      * */
diff --git a/src/api/java/ApplyResult.java b/src/api/java/ApplyResult.java
index 84c63e966..6fafbd888 100644
--- a/src/api/java/ApplyResult.java
+++ b/src/api/java/ApplyResult.java
@@ -21,8 +21,7 @@ package com.microsoft.z3;
  * ApplyResult objects represent the result of an application of a tactic to a
  * goal. It contains the subgoals that were produced.
  **/
-public class ApplyResult extends Z3Object
-{
+public class ApplyResult extends Z3Object {
     /**
      * The number of Subgoals.
      **/
@@ -64,15 +63,8 @@ public class ApplyResult extends Z3Object
      * A string representation of the ApplyResult.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.applyResultToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.applyResultToString(getContext().nCtx(), getNativeObject());
     }
 
     ApplyResult(Context ctx, long obj)
@@ -81,16 +73,12 @@ public class ApplyResult extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getApplyResultDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.applyResultIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getApplyResultDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getApplyResultDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ApplyResultDecRefQueue.java b/src/api/java/ApplyResultDecRefQueue.java
index 63f315ecd..e1a660781 100644
--- a/src/api/java/ApplyResultDecRefQueue.java
+++ b/src/api/java/ApplyResultDecRefQueue.java
@@ -17,39 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class ApplyResultDecRefQueue extends IDecRefQueue
+class ApplyResultDecRefQueue extends IDecRefQueue<ApplyResult>
 {
     public ApplyResultDecRefQueue() 
     {
         super();
     }
 
-    public ApplyResultDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.applyResultIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.applyResultDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.applyResultDecRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/AstMapDecRefQueue.java b/src/api/java/AstMapDecRefQueue.java
index 1598f75e7..6c96970b7 100644
--- a/src/api/java/AstMapDecRefQueue.java
+++ b/src/api/java/AstMapDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class ASTMapDecRefQueue extends IDecRefQueue
-{
+class ASTMapDecRefQueue extends IDecRefQueue<ASTMap> {
     public ASTMapDecRefQueue() 
     {
         super();
     }
 
-    public ASTMapDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.astMapIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.astMapDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.astMapDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/AstVectorDecRefQueue.java b/src/api/java/AstVectorDecRefQueue.java
index a63d808d3..e7ce3e33e 100644
--- a/src/api/java/AstVectorDecRefQueue.java
+++ b/src/api/java/AstVectorDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class ASTVectorDecRefQueue extends IDecRefQueue
-{
+class ASTVectorDecRefQueue extends IDecRefQueue<ASTVector> {
     public ASTVectorDecRefQueue() 
     {
         super();
     }
 
-    public ASTVectorDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.astVectorIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.astVectorDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.astVectorDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/BitVecNum.java b/src/api/java/BitVecNum.java
index 5a62f8087..d6c176855 100644
--- a/src/api/java/BitVecNum.java
+++ b/src/api/java/BitVecNum.java
@@ -66,13 +66,7 @@ public class BitVecNum extends BitVecExpr
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.getNumeralString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.getNumeralString(getContext().nCtx(), getNativeObject());
     }
 
     BitVecNum(Context ctx, long obj)
diff --git a/src/api/java/BoolExpr.java b/src/api/java/BoolExpr.java
index 02eabd2b5..dc75b2e7c 100644
--- a/src/api/java/BoolExpr.java
+++ b/src/api/java/BoolExpr.java
@@ -20,15 +20,7 @@ package com.microsoft.z3;
 /**
  * Boolean expressions
  **/
-public class BoolExpr extends Expr
-{
-    /**
-     * Constructor for BoolExpr
-     **/
-    protected BoolExpr(Context ctx)
-    {
-        super(ctx);
-    }
+public class BoolExpr extends Expr {
 
     /**
      * Constructor for BoolExpr
diff --git a/src/api/java/Constructor.java b/src/api/java/Constructor.java
index a6c2856d4..87ab86c3f 100644
--- a/src/api/java/Constructor.java
+++ b/src/api/java/Constructor.java
@@ -20,8 +20,14 @@ package com.microsoft.z3;
 /**
  * Constructors are used for datatype sorts.
  **/
-public class Constructor extends Z3Object
-{
+public class Constructor extends Z3Object {
+    private final int n;
+
+    Constructor(Context ctx, int n, long nativeObj) {
+        super(ctx, nativeObj);
+        this.n = n;
+    }
+
     /**
      * The number of fields of the constructor.
      * @throws Z3Exception 
@@ -78,29 +84,19 @@ public class Constructor extends Z3Object
         return t;
     }
 
-    /**
-     * Destructor.
-     * @throws Throwable 
-     * @throws Z3Exception on error
-     **/
-    protected void finalize() throws Throwable
-    {
-        try {
-            Native.delConstructor(getContext().nCtx(), getNativeObject());
-        } finally {
-            super.finalize();
-        }
+    @Override
+    void incRef() {
+        // Datatype constructors are not reference counted.
     }
 
-    private int n = 0;
+    @Override
+    void addToReferenceQueue() {
+        getContext().getConstructorDRQ().storeReference(getContext(), this);
+    }
 
-    Constructor(Context ctx, Symbol name, Symbol recognizer,
-            Symbol[] fieldNames, Sort[] sorts, int[] sortRefs)
-           
-    {
-        super(ctx);
-
-        n = AST.arrayLength(fieldNames);
+    static Constructor of(Context ctx, Symbol name, Symbol recognizer,
+            Symbol[] fieldNames, Sort[] sorts, int[] sortRefs) {
+        int n = AST.arrayLength(fieldNames);
 
         if (n != AST.arrayLength(sorts))
             throw new Z3Exception(
@@ -112,9 +108,10 @@ public class Constructor extends Z3Object
         if (sortRefs == null)
             sortRefs = new int[n];
 
-        setNativeObject(Native.mkConstructor(ctx.nCtx(), name.getNativeObject(),
+        long nativeObj = Native.mkConstructor(ctx.nCtx(), name.getNativeObject(),
                 recognizer.getNativeObject(), n, Symbol.arrayToNative(fieldNames),
-                Sort.arrayToNative(sorts), sortRefs));
+                Sort.arrayToNative(sorts), sortRefs);
+        return new Constructor(ctx, n, nativeObj);
 
     }
 }
diff --git a/src/api/java/ConstructorDecRefQueue.java b/src/api/java/ConstructorDecRefQueue.java
new file mode 100644
index 000000000..5003dde5f
--- /dev/null
+++ b/src/api/java/ConstructorDecRefQueue.java
@@ -0,0 +1,12 @@
+package com.microsoft.z3;
+
+public class ConstructorDecRefQueue extends IDecRefQueue<Constructor> {
+    public ConstructorDecRefQueue() {
+        super();
+    }
+
+    @Override
+    protected void decRef(Context ctx, long obj) {
+        Native.delConstructor(ctx.nCtx(), obj);
+    }
+}
diff --git a/src/api/java/ConstructorList.java b/src/api/java/ConstructorList.java
index fe3fae1ac..c79e08d9e 100644
--- a/src/api/java/ConstructorList.java
+++ b/src/api/java/ConstructorList.java
@@ -20,32 +20,26 @@ package com.microsoft.z3;
 /**
  * Lists of constructors
  **/
-public class ConstructorList extends Z3Object
-{
-    /**
-     * Destructor.
-     * @throws Throwable 
-     * @throws Z3Exception on error
-     **/
-    protected void finalize() throws Throwable
-    {
-        try {        
-            Native.delConstructorList(getContext().nCtx(), getNativeObject());            
-        } finally {
-            super.finalize();
-        }
-    }
+public class ConstructorList extends Z3Object {
 
     ConstructorList(Context ctx, long obj)
     {
         super(ctx, obj);
     }
 
+    @Override
+    void incRef() {
+        // Constructor lists are not reference counted.
+    }
+
+    @Override
+    void addToReferenceQueue() {
+        getContext().getConstructorListDRQ().storeReference(getContext(), this);
+    }
+
     ConstructorList(Context ctx, Constructor[] constructors)
     {
-        super(ctx);
-
-        setNativeObject(Native.mkConstructorList(getContext().nCtx(),
+        super(ctx, Native.mkConstructorList(ctx.nCtx(),
                 constructors.length,
                 Constructor.arrayToNative(constructors)));
     }
diff --git a/src/api/java/ConstructorListDecRefQueue.java b/src/api/java/ConstructorListDecRefQueue.java
new file mode 100644
index 000000000..1a2460731
--- /dev/null
+++ b/src/api/java/ConstructorListDecRefQueue.java
@@ -0,0 +1,12 @@
+package com.microsoft.z3;
+
+public class ConstructorListDecRefQueue extends IDecRefQueue<ConstructorList> {
+    public ConstructorListDecRefQueue() {
+        super();
+    }
+
+    @Override
+    protected void decRef(Context ctx, long obj) {
+        Native.delConstructorList(ctx.nCtx(), obj);
+    }
+}
diff --git a/src/api/java/Context.java b/src/api/java/Context.java
index 9fa17fcd4..da924026c 100644
--- a/src/api/java/Context.java
+++ b/src/api/java/Context.java
@@ -17,34 +17,36 @@ Notes:
 
 package com.microsoft.z3;
 
-import java.util.Map;
-import java.util.concurrent.atomic.AtomicInteger;
+import static com.microsoft.z3.Constructor.of;
 
 import com.microsoft.z3.enumerations.Z3_ast_print_mode;
 
+import java.util.Map;
+
 /**
  * The main interaction with Z3 happens via the Context.
  **/
-public class Context extends IDisposable
-{
-    /**
-     * Constructor.
-     **/
-    public Context()
-    {        
-        super();
-        synchronized (creation_lock) {            
-            m_ctx = Native.mkContextRc(0);
-            initContext();
-        }
+public class Context implements AutoCloseable {
+    private final long m_ctx;
+    static final Object creation_lock = new Object();
+
+    public Context () {
+        m_ctx = Native.mkContextRc(0);
+        init();
     }
 
+    protected Context (long m_ctx) {
+        this.m_ctx = m_ctx;
+        init();
+    }
+
+
     /**
      * Constructor.
      * Remarks:
-     * The following parameters can be set:        
+     * The following parameters can be set:
      *     - proof  (Boolean)           Enable proof generation
-     *     - debug_ref_count (Boolean)  Enable debug support for Z3_ast reference counting 
+     *     - debug_ref_count (Boolean)  Enable debug support for Z3_ast reference counting
      *     - trace  (Boolean)           Tracing support for VCC
      *     - trace_file_name (String)   Trace out file for VCC traces
      *     - timeout (unsigned)         default timeout (in milliseconds) used for solvers
@@ -53,20 +55,22 @@ public class Context extends IDisposable
      *     - model                      model generation for solvers, this parameter can be overwritten when creating a solver
      *     - model_validate             validate models produced by solvers
      *     - unsat_core                 unsat-core generation for solvers, this parameter can be overwritten when creating a solver
-     * Note that in previous versions of Z3, this constructor was also used to set global and 
+     * Note that in previous versions of Z3, this constructor was also used to set global and
      * module parameters. For this purpose we should now use {@code Global.setParameter}
      **/
-    public Context(Map<String, String> settings)
-    {
-        super();
-        synchronized (creation_lock) {            
-            long cfg = Native.mkConfig();
-            for (Map.Entry<String, String> kv : settings.entrySet())
-                Native.setParamValue(cfg, kv.getKey(), kv.getValue());
-            m_ctx = Native.mkContextRc(cfg);
-            Native.delConfig(cfg);
-            initContext();
+    public Context(Map<String, String> settings) {
+        long cfg = Native.mkConfig();
+        for (Map.Entry<String, String> kv : settings.entrySet()) {
+            Native.setParamValue(cfg, kv.getKey(), kv.getValue());
         }
+        m_ctx = Native.mkContextRc(cfg);
+        Native.delConfig(cfg);
+        init();
+    }
+
+    private void init() {
+        setPrintMode(Z3_ast_print_mode.Z3_PRINT_SMTLIB2_COMPLIANT);
+        Native.setInternalErrorHandler(m_ctx);
     }
 
     /**
@@ -242,7 +246,7 @@ public class Context extends IDisposable
         checkContextMatch(name);
         checkContextMatch(fieldNames);
         checkContextMatch(fieldSorts);
-        return new TupleSort(this, name, (int) fieldNames.length, fieldNames,
+        return new TupleSort(this, name, fieldNames.length, fieldNames,
                 fieldSorts);
     }
 
@@ -319,8 +323,7 @@ public class Context extends IDisposable
             Symbol[] fieldNames, Sort[] sorts, int[] sortRefs)
            
     {
-
-        return new Constructor(this, name, recognizer, fieldNames, sorts,
+        return of(this, name, recognizer, fieldNames, sorts,
                 sortRefs);
     }
 
@@ -329,10 +332,8 @@ public class Context extends IDisposable
      **/
     public Constructor mkConstructor(String name, String recognizer,
             String[] fieldNames, Sort[] sorts, int[] sortRefs)
-           
     {
-
-        return new Constructor(this, mkSymbol(name), mkSymbol(recognizer),
+        return of(this, mkSymbol(name), mkSymbol(recognizer),
                 mkSymbols(fieldNames), sorts, sortRefs);
     }
 
@@ -525,7 +526,7 @@ public class Context extends IDisposable
             throw new Z3Exception("Cannot create a pattern from zero terms");
 
         long[] termsNative = AST.arrayToNative(terms);
-        return new Pattern(this, Native.mkPattern(nCtx(), (int) terms.length,
+        return new Pattern(this, Native.mkPattern(nCtx(), terms.length,
                 termsNative));
     }
 
@@ -688,7 +689,7 @@ public class Context extends IDisposable
     public BoolExpr mkDistinct(Expr... args)
     {
         checkContextMatch(args);
-        return new BoolExpr(this, Native.mkDistinct(nCtx(), (int) args.length,
+        return new BoolExpr(this, Native.mkDistinct(nCtx(), args.length,
                 AST.arrayToNative(args)));
     }
 
@@ -756,7 +757,7 @@ public class Context extends IDisposable
     public BoolExpr mkAnd(BoolExpr... t)
     {
         checkContextMatch(t);
-        return new BoolExpr(this, Native.mkAnd(nCtx(), (int) t.length,
+        return new BoolExpr(this, Native.mkAnd(nCtx(), t.length,
                 AST.arrayToNative(t)));
     }
 
@@ -766,7 +767,7 @@ public class Context extends IDisposable
     public BoolExpr mkOr(BoolExpr... t)
     {
         checkContextMatch(t);
-        return new BoolExpr(this, Native.mkOr(nCtx(), (int) t.length,
+        return new BoolExpr(this, Native.mkOr(nCtx(), t.length,
                 AST.arrayToNative(t)));
     }
 
@@ -777,7 +778,7 @@ public class Context extends IDisposable
     {
         checkContextMatch(t);
         return (ArithExpr) Expr.create(this,
-                Native.mkAdd(nCtx(), (int) t.length, AST.arrayToNative(t)));
+                Native.mkAdd(nCtx(), t.length, AST.arrayToNative(t)));
     }
 
     /**
@@ -787,7 +788,7 @@ public class Context extends IDisposable
     {
         checkContextMatch(t);
         return (ArithExpr) Expr.create(this,
-                Native.mkMul(nCtx(), (int) t.length, AST.arrayToNative(t)));
+                Native.mkMul(nCtx(), t.length, AST.arrayToNative(t)));
     }
 
     /**
@@ -797,7 +798,7 @@ public class Context extends IDisposable
     {
         checkContextMatch(t);
         return (ArithExpr) Expr.create(this,
-                Native.mkSub(nCtx(), (int) t.length, AST.arrayToNative(t)));
+                Native.mkSub(nCtx(), t.length, AST.arrayToNative(t)));
     }
 
     /**
@@ -1814,7 +1815,7 @@ public class Context extends IDisposable
     {
         checkContextMatch(args);
         return (ArrayExpr)Expr.create(this,
-                Native.mkSetUnion(nCtx(), (int) args.length,
+                Native.mkSetUnion(nCtx(), args.length,
                         AST.arrayToNative(args)));
     }
 
@@ -1825,7 +1826,7 @@ public class Context extends IDisposable
     {
         checkContextMatch(args);
         return (ArrayExpr)Expr.create(this,
-                Native.mkSetIntersect(nCtx(), (int) args.length,
+                Native.mkSetIntersect(nCtx(), args.length,
                         AST.arrayToNative(args)));
     }
 
@@ -1912,7 +1913,7 @@ public class Context extends IDisposable
     public SeqExpr MkConcat(SeqExpr... t)
     {
 	checkContextMatch(t);
-	return new SeqExpr(this, Native.mkSeqConcat(nCtx(), (int)t.length, AST.arrayToNative(t)));
+	return new SeqExpr(this, Native.mkSeqConcat(nCtx(), t.length, AST.arrayToNative(t)));
     }
     
     
@@ -2040,7 +2041,7 @@ public class Context extends IDisposable
     public ReExpr MkConcat(ReExpr... t)
     {
 	checkContextMatch(t);
-	return new ReExpr(this, Native.mkReConcat(nCtx(), (int)t.length, AST.arrayToNative(t)));
+	return new ReExpr(this, Native.mkReConcat(nCtx(), t.length, AST.arrayToNative(t)));
     }
     
     /**
@@ -2049,7 +2050,7 @@ public class Context extends IDisposable
     public ReExpr MkUnion(ReExpr... t)
     {
 	checkContextMatch(t);
-	return new ReExpr(this, Native.mkReUnion(nCtx(), (int)t.length, AST.arrayToNative(t)));
+	return new ReExpr(this, Native.mkReUnion(nCtx(), t.length, AST.arrayToNative(t)));
     }
     
 
@@ -2258,7 +2259,7 @@ public class Context extends IDisposable
                                Symbol quantifierID, Symbol skolemID)
     {
 
-        return new Quantifier(this, true, sorts, names, body, weight, patterns,
+        return Quantifier.of(this, true, sorts, names, body, weight, patterns,
                 noPatterns, quantifierID, skolemID);
     }
 
@@ -2271,7 +2272,7 @@ public class Context extends IDisposable
                                Symbol skolemID)
     {
 
-        return new Quantifier(this, true, boundConstants, body, weight,
+        return Quantifier.of(this, true, boundConstants, body, weight,
                 patterns, noPatterns, quantifierID, skolemID);
     }
 
@@ -2284,7 +2285,7 @@ public class Context extends IDisposable
                                Symbol quantifierID, Symbol skolemID)
     {
 
-        return new Quantifier(this, false, sorts, names, body, weight,
+        return Quantifier.of(this, false, sorts, names, body, weight,
                 patterns, noPatterns, quantifierID, skolemID);
     }
 
@@ -2297,7 +2298,7 @@ public class Context extends IDisposable
                                Symbol skolemID)
     {
 
-        return new Quantifier(this, false, boundConstants, body, weight,
+        return Quantifier.of(this, false, boundConstants, body, weight,
                 patterns, noPatterns, quantifierID, skolemID);
     }
 
@@ -3814,7 +3815,7 @@ public class Context extends IDisposable
      * must be a native object obtained from Z3 (e.g., through 
      * {@code UnwrapAST}) and that it must have a correct reference count.
      * @see Native#incRef 
-     * @see unwrapAST
+     * @see #unwrapAST
      * @param nativeObject The native pointer to wrap.
      **/
     public AST wrapAST(long nativeObject)
@@ -3869,19 +3870,12 @@ public class Context extends IDisposable
         Native.updateParamValue(nCtx(), id, value);
     }
 
-    protected long m_ctx = 0;
-    protected static final Object creation_lock = new Object();
 
     long nCtx()
     {
         return m_ctx;
     }
 
-    void initContext()
-    {
-        setPrintMode(Z3_ast_print_mode.Z3_PRINT_SMTLIB2_COMPLIANT);
-        Native.setInternalErrorHandler(nCtx());
-    }
 
     void checkContextMatch(Z3Object other)
     {
@@ -3910,125 +3904,118 @@ public class Context extends IDisposable
     }
 
     private ASTDecRefQueue m_AST_DRQ = new ASTDecRefQueue();
-    private ASTMapDecRefQueue m_ASTMap_DRQ = new ASTMapDecRefQueue(10);
-    private ASTVectorDecRefQueue m_ASTVector_DRQ = new ASTVectorDecRefQueue(10);
-    private ApplyResultDecRefQueue m_ApplyResult_DRQ = new ApplyResultDecRefQueue(10);
-    private FuncInterpEntryDecRefQueue m_FuncEntry_DRQ = new FuncInterpEntryDecRefQueue(10);
-    private FuncInterpDecRefQueue m_FuncInterp_DRQ = new FuncInterpDecRefQueue(10);
-    private GoalDecRefQueue m_Goal_DRQ = new GoalDecRefQueue(10);
-    private ModelDecRefQueue m_Model_DRQ = new ModelDecRefQueue(10);
-    private ParamsDecRefQueue m_Params_DRQ = new ParamsDecRefQueue(10);
-    private ParamDescrsDecRefQueue m_ParamDescrs_DRQ = new ParamDescrsDecRefQueue(10);
-    private ProbeDecRefQueue m_Probe_DRQ = new ProbeDecRefQueue(10);
-    private SolverDecRefQueue m_Solver_DRQ = new SolverDecRefQueue(10);
-    private StatisticsDecRefQueue m_Statistics_DRQ = new StatisticsDecRefQueue(10);
-    private TacticDecRefQueue m_Tactic_DRQ = new TacticDecRefQueue(10);
-    private FixedpointDecRefQueue m_Fixedpoint_DRQ = new FixedpointDecRefQueue(10);
-    private OptimizeDecRefQueue m_Optimize_DRQ = new OptimizeDecRefQueue(10);
+    private ASTMapDecRefQueue m_ASTMap_DRQ = new ASTMapDecRefQueue();
+    private ASTVectorDecRefQueue m_ASTVector_DRQ = new ASTVectorDecRefQueue();
+    private ApplyResultDecRefQueue m_ApplyResult_DRQ = new ApplyResultDecRefQueue();
+    private FuncInterpEntryDecRefQueue m_FuncEntry_DRQ = new FuncInterpEntryDecRefQueue();
+    private FuncInterpDecRefQueue m_FuncInterp_DRQ = new FuncInterpDecRefQueue();
+    private GoalDecRefQueue m_Goal_DRQ = new GoalDecRefQueue();
+    private ModelDecRefQueue m_Model_DRQ = new ModelDecRefQueue();
+    private ParamsDecRefQueue m_Params_DRQ = new ParamsDecRefQueue();
+    private ParamDescrsDecRefQueue m_ParamDescrs_DRQ = new ParamDescrsDecRefQueue();
+    private ProbeDecRefQueue m_Probe_DRQ = new ProbeDecRefQueue();
+    private SolverDecRefQueue m_Solver_DRQ = new SolverDecRefQueue();
+    private StatisticsDecRefQueue m_Statistics_DRQ = new StatisticsDecRefQueue();
+    private TacticDecRefQueue m_Tactic_DRQ = new TacticDecRefQueue();
+    private FixedpointDecRefQueue m_Fixedpoint_DRQ = new FixedpointDecRefQueue();
+    private OptimizeDecRefQueue m_Optimize_DRQ = new OptimizeDecRefQueue();
+    private ConstructorDecRefQueue m_Constructor_DRQ = new ConstructorDecRefQueue();
+    private ConstructorListDecRefQueue m_ConstructorList_DRQ =
+            new ConstructorListDecRefQueue();
 
-    public IDecRefQueue getASTDRQ()
+    public IDecRefQueue<Constructor> getConstructorDRQ() {
+        return m_Constructor_DRQ;
+    }
+
+    public IDecRefQueue<ConstructorList> getConstructorListDRQ() {
+        return m_ConstructorList_DRQ;
+    }
+
+    public IDecRefQueue<AST> getASTDRQ()
     {
         return m_AST_DRQ;
     }
 
-    public IDecRefQueue getASTMapDRQ()
+    public IDecRefQueue<ASTMap> getASTMapDRQ()
     {
         return m_ASTMap_DRQ;
     }
 
-    public IDecRefQueue getASTVectorDRQ()
+    public IDecRefQueue<ASTVector> getASTVectorDRQ()
     {
         return m_ASTVector_DRQ;
     }
 
-    public IDecRefQueue getApplyResultDRQ()
+    public IDecRefQueue<ApplyResult> getApplyResultDRQ()
     {
         return m_ApplyResult_DRQ;
     }
 
-    public IDecRefQueue getFuncEntryDRQ()
+    public IDecRefQueue<FuncInterp.Entry> getFuncEntryDRQ()
     {
         return m_FuncEntry_DRQ;
     }
 
-    public IDecRefQueue getFuncInterpDRQ()
+    public IDecRefQueue<FuncInterp> getFuncInterpDRQ()
     {
         return m_FuncInterp_DRQ;
     }
 
-    public IDecRefQueue getGoalDRQ()
+    public IDecRefQueue<Goal> getGoalDRQ()
     {
         return m_Goal_DRQ;
     }
 
-    public IDecRefQueue getModelDRQ()
+    public IDecRefQueue<Model> getModelDRQ()
     {
         return m_Model_DRQ;
     }
 
-    public IDecRefQueue getParamsDRQ()
+    public IDecRefQueue<Params> getParamsDRQ()
     {
         return m_Params_DRQ;
     }
 
-    public IDecRefQueue getParamDescrsDRQ()
+    public IDecRefQueue<ParamDescrs> getParamDescrsDRQ()
     {
         return m_ParamDescrs_DRQ;
     }
 
-    public IDecRefQueue getProbeDRQ()
+    public IDecRefQueue<Probe> getProbeDRQ()
     {
         return m_Probe_DRQ;
     }
 
-    public IDecRefQueue getSolverDRQ()
+    public IDecRefQueue<Solver> getSolverDRQ()
     {
         return m_Solver_DRQ;
     }
 
-    public IDecRefQueue getStatisticsDRQ()
+    public IDecRefQueue<Statistics> getStatisticsDRQ()
     {
         return m_Statistics_DRQ;
     }
 
-    public IDecRefQueue getTacticDRQ()
+    public IDecRefQueue<Tactic> getTacticDRQ()
     {
         return m_Tactic_DRQ;
     }
 
-    public IDecRefQueue getFixedpointDRQ()
+    public IDecRefQueue<Fixedpoint> getFixedpointDRQ()
     {
         return m_Fixedpoint_DRQ;
     }
 
-    public IDecRefQueue getOptimizeDRQ()
+    public IDecRefQueue<Optimize> getOptimizeDRQ()
     {
         return m_Optimize_DRQ;
     }
 
-    protected AtomicInteger m_refCount = new AtomicInteger(0);
-
-    /**
-     * Finalizer.
-     * @throws Throwable 
-     **/
-    protected void finalize() throws Throwable
-    {
-        try {            
-            dispose();
-        }
-        catch (Throwable t) {
-            throw t;
-        }
-        finally {
-            super.finalize();
-        }
-    }
-
     /**
      * Disposes of the context.
      **/
-    public void dispose()
+    @Override
+    public void close()
     {
         m_AST_DRQ.clear(this);
         m_ASTMap_DRQ.clear(this);
@@ -4051,16 +4038,6 @@ public class Context extends IDisposable
         m_realSort = null;
         m_stringSort = null;
 
-        synchronized (creation_lock) {
-            if (m_refCount.get() == 0 && m_ctx != 0) {
-                try {
-                    Native.delContext(m_ctx);
-                } catch (Z3Exception e) {
-                    // OK?
-                    System.out.println("Context deletion failed; memory leak possible.");
-                }
-                m_ctx = 0;
-            }
-        }
+        Native.delContext(m_ctx);
     }
 }
diff --git a/src/api/java/EnumSort.java b/src/api/java/EnumSort.java
index bb60eef56..ce2f8d578 100644
--- a/src/api/java/EnumSort.java
+++ b/src/api/java/EnumSort.java
@@ -92,13 +92,9 @@ public class EnumSort extends Sort
 
     EnumSort(Context ctx, Symbol name, Symbol[] enumNames)
     {
-        super(ctx, 0);
-
-        int n = enumNames.length;
-        long[] n_constdecls = new long[n];
-        long[] n_testers = new long[n];
-        setNativeObject(Native.mkEnumerationSort(ctx.nCtx(),
-                name.getNativeObject(), n, Symbol.arrayToNative(enumNames),
-                n_constdecls, n_testers));        
+        super(ctx, Native.mkEnumerationSort(ctx.nCtx(),
+                name.getNativeObject(), enumNames.length,
+                Symbol.arrayToNative(enumNames),
+                new long[enumNames.length], new long[enumNames.length]));
     }
 };
diff --git a/src/api/java/Expr.java b/src/api/java/Expr.java
index b24d3ac62..ea3fd2147 100644
--- a/src/api/java/Expr.java
+++ b/src/api/java/Expr.java
@@ -120,13 +120,13 @@ public class Expr extends AST
      * @param args arguments
      * @throws Z3Exception on error
      **/
-    public void update(Expr[] args)
+    public Expr update(Expr[] args)
     {
         getContext().checkContextMatch(args);
         if (isApp() && args.length != getNumArgs()) {
             throw new Z3Exception("Number of arguments does not match");
         }
-        setNativeObject(Native.updateTerm(getContext().nCtx(), getNativeObject(),
+        return new Expr(getContext(), Native.updateTerm(getContext().nCtx(), getNativeObject(),
                 args.length, Expr.arrayToNative(args)));
     }
 
@@ -2091,36 +2091,23 @@ public class Expr extends AST
      **/
     public int getIndex()
     {
-        if (!isVar())
+        if (!isVar()) {
             throw new Z3Exception("Term is not a bound variable.");
+        }
 
         return Native.getIndexValue(getContext().nCtx(), getNativeObject());
     }
 
-    /**
-     * Constructor for Expr
-     **/
-    protected Expr(Context ctx)
-    {
-        super(ctx);
-        {
-        }
-    }
-
     /**
      * Constructor for Expr
      * @throws Z3Exception on error
      **/
-    protected Expr(Context ctx, long obj)
-    {
+    protected Expr(Context ctx, long obj) {
         super(ctx, obj);
-        {
-        }
     }
 
     @Override
-    void checkNativeObject(long obj)
-    {
+    void checkNativeObject(long obj) {
         if (!Native.isApp(getContext().nCtx(), obj) && 
             Native.getAstKind(getContext().nCtx(), obj) != Z3_ast_kind.Z3_VAR_AST.toInt() &&
             Native.getAstKind(getContext().nCtx(), obj) != Z3_ast_kind.Z3_QUANTIFIER_AST.toInt()) {
diff --git a/src/api/java/FPNum.java b/src/api/java/FPNum.java
index 69a44c559..402d25ebe 100644
--- a/src/api/java/FPNum.java
+++ b/src/api/java/FPNum.java
@@ -28,7 +28,7 @@ public class FPNum extends FPExpr
      */
     public boolean getSign() {
         Native.IntPtr res = new Native.IntPtr();
-        if (Native.fpaGetNumeralSign(getContext().nCtx(), getNativeObject(), res) ^ true)                
+        if (!Native.fpaGetNumeralSign(getContext().nCtx(), getNativeObject(), res))
             throw new Z3Exception("Sign is not a Boolean value");
         return res.value != 0;
     }
@@ -53,7 +53,7 @@ public class FPNum extends FPExpr
     public long getSignificandUInt64()
     {
         Native.LongPtr res = new Native.LongPtr();
-        if (Native.fpaGetNumeralSignificandUint64(getContext().nCtx(), getNativeObject(), res) ^ true)
+        if (!Native.fpaGetNumeralSignificandUint64(getContext().nCtx(), getNativeObject(), res))
             throw new Z3Exception("Significand is not a 64 bit unsigned integer");
         return res.value;
     }
@@ -72,7 +72,7 @@ public class FPNum extends FPExpr
      */
     public long getExponentInt64()  {
         Native.LongPtr res = new Native.LongPtr();
-        if (Native.fpaGetNumeralExponentInt64(getContext().nCtx(), getNativeObject(), res) ^ true)
+        if (!Native.fpaGetNumeralExponentInt64(getContext().nCtx(), getNativeObject(), res))
             throw new Z3Exception("Exponent is not a 64 bit integer");
         return res.value;
     }
@@ -87,13 +87,7 @@ public class FPNum extends FPExpr
      */           
     public String toString()
     {
-        try
-        {
-            return Native.getNumeralString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.getNumeralString(getContext().nCtx(), getNativeObject());
     }
 
 }
diff --git a/src/api/java/FiniteDomainNum.java b/src/api/java/FiniteDomainNum.java
index e53ed22b2..68467e408 100644
--- a/src/api/java/FiniteDomainNum.java
+++ b/src/api/java/FiniteDomainNum.java
@@ -68,12 +68,6 @@ public class FiniteDomainNum extends FiniteDomainExpr
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.getNumeralString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.getNumeralString(getContext().nCtx(), getNativeObject());
     }
 }
diff --git a/src/api/java/Fixedpoint.java b/src/api/java/Fixedpoint.java
index 14fb3a44a..876345f1e 100644
--- a/src/api/java/Fixedpoint.java
+++ b/src/api/java/Fixedpoint.java
@@ -255,14 +255,8 @@ public class Fixedpoint extends Z3Object
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.fixedpointToString(getContext().nCtx(), getNativeObject(),
+        return Native.fixedpointToString(getContext().nCtx(), getNativeObject(),
                     0, null);
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
     }
 
     /**
@@ -355,16 +349,15 @@ public class Fixedpoint extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getFixedpointDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.fixedpointIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getFixedpointDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getFixedpointDRQ().storeReference(getContext(), this);
     }
+
+    @Override
+    void checkNativeObject(long obj) { }
 }
diff --git a/src/api/java/FixedpointDecRefQueue.java b/src/api/java/FixedpointDecRefQueue.java
index e65538a30..69ed82092 100644
--- a/src/api/java/FixedpointDecRefQueue.java
+++ b/src/api/java/FixedpointDecRefQueue.java
@@ -17,39 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class FixedpointDecRefQueue extends IDecRefQueue
-{
+class FixedpointDecRefQueue extends IDecRefQueue<Fixedpoint> {
     public FixedpointDecRefQueue() 
     {
         super();
     }
 
-    public FixedpointDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
-    @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.fixedpointIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
     @Override
     protected void decRef(Context ctx, long obj)
     {
-        try
-        {
-            Native.fixedpointDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+        Native.fixedpointDecRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/FuncDecl.java b/src/api/java/FuncDecl.java
index 301978c44..273e853c0 100644
--- a/src/api/java/FuncDecl.java
+++ b/src/api/java/FuncDecl.java
@@ -47,13 +47,7 @@ public class FuncDecl extends AST
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.funcDeclToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.funcDeclToString(getContext().nCtx(), getNativeObject());
     }
 
     /**
diff --git a/src/api/java/FuncInterp.java b/src/api/java/FuncInterp.java
index 72f6bb25d..b5873d98e 100644
--- a/src/api/java/FuncInterp.java
+++ b/src/api/java/FuncInterp.java
@@ -22,20 +22,20 @@ package com.microsoft.z3;
  * Each entry in the finite map represents the value of a function given a set
  * of arguments.
  **/
-public class FuncInterp extends Z3Object
-{
+public class FuncInterp extends Z3Object {
+
     /**
      * An Entry object represents an element in the finite map used to encode a
      * function interpretation.
      **/
-    public class Entry extends Z3Object
-    {
+    public static class Entry extends Z3Object {
+
         /**
          * Return the (symbolic) value of this entry.
-         * 
+         *
          * @throws Z3Exception
          * @throws Z3Exception on error
-     **/
+         **/
         public Expr getValue()
         {
             return Expr.create(getContext(),
@@ -45,7 +45,7 @@ public class FuncInterp extends Z3Object
         /**
          * The number of arguments of the entry.
          * @throws Z3Exception on error
-     **/
+         **/
         public int getNumArgs()
         {
             return Native.funcEntryGetNumArgs(getContext().nCtx(), getNativeObject());
@@ -53,10 +53,10 @@ public class FuncInterp extends Z3Object
 
         /**
          * The arguments of the function entry.
-         * 
+         *
          * @throws Z3Exception
          * @throws Z3Exception on error
-     **/
+         **/
         public Expr[] getArgs()
         {
             int n = getNumArgs();
@@ -73,37 +73,26 @@ public class FuncInterp extends Z3Object
         @Override
         public String toString()
         {
-            try
-            {
-                int n = getNumArgs();
-                String res = "[";
-                Expr[] args = getArgs();
-                for (int i = 0; i < n; i++)
-                    res += args[i] + ", ";
-                return res + getValue() + "]";
-            } catch (Z3Exception e)
-            {
-                return "Z3Exception: " + e.getMessage();
-            }
+            int n = getNumArgs();
+            String res = "[";
+            Expr[] args = getArgs();
+            for (int i = 0; i < n; i++)
+                res += args[i] + ", ";
+            return res + getValue() + "]";
         }
 
-        Entry(Context ctx, long obj)
-        {
+        Entry(Context ctx, long obj) {
             super(ctx, obj);
         }
 
         @Override
-        void incRef(long o)
-        {
-            getContext().getFuncEntryDRQ().incAndClear(getContext(), o);
-            super.incRef(o);
+        void incRef() {
+            Native.funcEntryIncRef(getContext().nCtx(), getNativeObject());
         }
 
         @Override
-        void decRef(long o)
-        {
-            getContext().getFuncEntryDRQ().add(o);
-            super.decRef(o);
+        void addToReferenceQueue() {
+            getContext().getFuncEntryDRQ().storeReference(getContext(), this);
         }
     }
 
@@ -161,33 +150,27 @@ public class FuncInterp extends Z3Object
      **/
     public String toString()
     {
-        try
+        String res = "";
+        res += "[";
+        for (Entry e : getEntries())
         {
-            String res = "";
-            res += "[";
-            for (Entry e : getEntries())
+            int n = e.getNumArgs();
+            if (n > 1)
+                res += "[";
+            Expr[] args = e.getArgs();
+            for (int i = 0; i < n; i++)
             {
-                int n = e.getNumArgs();
-                if (n > 1)
-                    res += "[";
-                Expr[] args = e.getArgs();
-                for (int i = 0; i < n; i++)
-                {
-                    if (i != 0)
-                        res += ", ";
-                    res += args[i];
-                }
-                if (n > 1)
-                    res += "]";
-                res += " -> " + e.getValue() + ", ";
+                if (i != 0)
+                    res += ", ";
+                res += args[i];
             }
-            res += "else -> " + getElse();
-            res += "]";
-            return res;
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
+            if (n > 1)
+                res += "]";
+            res += " -> " + e.getValue() + ", ";
         }
+        res += "else -> " + getElse();
+        res += "]";
+        return res;
     }
 
     FuncInterp(Context ctx, long obj)
@@ -196,16 +179,12 @@ public class FuncInterp extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getFuncInterpDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.funcInterpIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getFuncInterpDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getFuncInterpDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/FuncInterpDecRefQueue.java b/src/api/java/FuncInterpDecRefQueue.java
index c888e9e3d..d8715bd0e 100644
--- a/src/api/java/FuncInterpDecRefQueue.java
+++ b/src/api/java/FuncInterpDecRefQueue.java
@@ -17,39 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class FuncInterpDecRefQueue extends IDecRefQueue
+class FuncInterpDecRefQueue extends IDecRefQueue<FuncInterp>
 {
     public FuncInterpDecRefQueue() 
     {
         super();
     }
 
-    public FuncInterpDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.funcInterpIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.funcInterpDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.funcInterpDecRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/FuncInterpEntryDecRefQueue.java b/src/api/java/FuncInterpEntryDecRefQueue.java
index 7dfdaa27d..a4d8a0690 100644
--- a/src/api/java/FuncInterpEntryDecRefQueue.java
+++ b/src/api/java/FuncInterpEntryDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class FuncInterpEntryDecRefQueue extends IDecRefQueue
-{
+class FuncInterpEntryDecRefQueue extends IDecRefQueue<FuncInterp.Entry> {
     public FuncInterpEntryDecRefQueue() 
     {
         super();
     }
 
-    public FuncInterpEntryDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.funcEntryIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.funcEntryDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.funcEntryDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/Goal.java b/src/api/java/Goal.java
index 46b04f6bf..25b1fe511 100644
--- a/src/api/java/Goal.java
+++ b/src/api/java/Goal.java
@@ -23,8 +23,7 @@ import com.microsoft.z3.enumerations.Z3_goal_prec;
  * A goal (aka problem). A goal is essentially a set of formulas, that can be
  * solved and/or transformed using tactics and solvers.
  **/
-public class Goal extends Z3Object
-{
+public class Goal extends Z3Object {
     /**
      * The precision of the goal.
      * Remarks:  Goals can be transformed using over
@@ -211,15 +210,8 @@ public class Goal extends Z3Object
      * 
      * @return A string representation of the Goal.
      **/
-    public String toString()
-    {
-        try
-        {
-            return Native.goalToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.goalToString(getContext().nCtx(), getNativeObject());
     }
     
     /** 
@@ -229,11 +221,11 @@ public class Goal extends Z3Object
      **/
     public BoolExpr AsBoolExpr() {
         int n = size();
-        if (n == 0) 
+        if (n == 0) {
             return getContext().mkTrue();
-        else if (n == 1)                
+        } else if (n == 1) {
             return getFormulas()[0];
-        else {
+        } else {
             return getContext().mkAnd(getFormulas());
         }
     }
@@ -243,23 +235,18 @@ public class Goal extends Z3Object
         super(ctx, obj);
     }
 
-    Goal(Context ctx, boolean models, boolean unsatCores, boolean proofs)
-           
-    {
+    Goal(Context ctx, boolean models, boolean unsatCores, boolean proofs) {
         super(ctx, Native.mkGoal(ctx.nCtx(), (models),
             (unsatCores), (proofs)));
     }
 
-    void incRef(long o)
-    {
-        getContext().getGoalDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    @Override
+    void incRef() {
+        Native.goalIncRef(getContext().nCtx(), getNativeObject());
     }
 
-    void decRef(long o)
-    {
-        getContext().getGoalDRQ().add(o);
-        super.decRef(o);
+    @Override
+    void addToReferenceQueue() {
+        getContext().getGoalDRQ().storeReference(getContext(), this);
     }
-
 }
diff --git a/src/api/java/GoalDecRefQueue.java b/src/api/java/GoalDecRefQueue.java
index be921241b..90bad1fb1 100644
--- a/src/api/java/GoalDecRefQueue.java
+++ b/src/api/java/GoalDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class GoalDecRefQueue extends IDecRefQueue
-{
+class GoalDecRefQueue extends IDecRefQueue<Goal> {
     public GoalDecRefQueue() 
     {
         super();
     }
 
-    public GoalDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.goalIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
+    protected void decRef(Context ctx, long obj) {
             Native.goalDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
     }
-};
+}
diff --git a/src/api/java/IDecRefQueue.java b/src/api/java/IDecRefQueue.java
index 1a99a3d92..2deb9c0f9 100644
--- a/src/api/java/IDecRefQueue.java
+++ b/src/api/java/IDecRefQueue.java
@@ -17,55 +17,54 @@ Notes:
 
 package com.microsoft.z3;
 
-import java.util.LinkedList;
+import java.lang.ref.PhantomReference;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.util.IdentityHashMap;
+import java.util.Map;
 
-public abstract class IDecRefQueue
-{
-    protected final Object m_lock = new Object();
-    protected LinkedList<Long> m_queue = new LinkedList<Long>();
-    protected int m_move_limit;
+/**
+ * A queue to handle management of native memory.
+ *
+ * <p><b>Mechanics: </b>once an object is created, a metadata is stored for it in
+ * {@code referenceMap}, and a {@link PhantomReference} is created with a
+ * reference  to {@code referenceQueue}.
+ * Once the object becomes strongly unreachable, the phantom reference gets
+ * added by JVM to the {@code referenceQueue}.
+ * After each object creation, we iterate through the available objects in
+ * {@code referenceQueue} and decrement references for them.
+ *
+ * @param <T> Type of object stored in queue.
+ */
+public abstract class IDecRefQueue<T extends Z3Object> {
+    private final ReferenceQueue<T> referenceQueue = new ReferenceQueue<>();
+    private final Map<PhantomReference<T>, Long> referenceMap =
+            new IdentityHashMap<>();
 
-    protected IDecRefQueue() 
-	{
-    	m_move_limit = 1024;
-    }
-
-    protected IDecRefQueue(int move_limit) 
-    {
-    	m_move_limit = move_limit;
-    }
- 
-    public void setLimit(int l) { m_move_limit = l; }
- 
-    protected abstract void incRef(Context ctx, long obj);
+    protected IDecRefQueue() {}
 
+    /**
+     * An implementation of this method should decrement the reference on a
+     * given native object.
+     * This function should always be called on the {@code ctx} thread.
+     *
+     * @param ctx Z3 context.
+     * @param obj Pointer to a Z3 object.
+     */
     protected abstract void decRef(Context ctx, long obj);
 
-    protected void incAndClear(Context ctx, long o)
-    {
-        incRef(ctx, o);
-        if (m_queue.size() >= m_move_limit)
-            clear(ctx);
-    }
-
-    protected void add(long o)
-    {
-        if (o == 0)
-            return;
-
-        synchronized (m_lock)
-        {
-            m_queue.add(o);
-        }
+    public void storeReference(Context ctx, T obj) {
+        PhantomReference<T> ref = new PhantomReference<>(obj, referenceQueue);
+        referenceMap.put(ref, obj.getNativeObject());
+        clear(ctx);
     }
 
     protected void clear(Context ctx)
     {
-        synchronized (m_lock)
-        {
-            for (Long o : m_queue)
-                decRef(ctx, o);
-            m_queue.clear();
+        Reference<? extends T> ref;
+        while ((ref = referenceQueue.poll()) != null) {
+            long z3ast = referenceMap.remove(ref);
+            decRef(ctx, z3ast);
         }
     }
 }
diff --git a/src/api/java/IDisposable.java b/src/api/java/IDisposable.java
deleted file mode 100644
index dae8a7262..000000000
--- a/src/api/java/IDisposable.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/*++
-Copyright (c) 2012 Microsoft Corporation
-
-Module Name:
-
-    IDisposable.java
-
-Abstract:
-
-    Compatability interface (C# -> Java)
-
-Author:
-
-    Christoph Wintersteiger (cwinter) 2012-03-16
-
-Notes:
-    
---*/
-
-package com.microsoft.z3;
-
-public abstract class IDisposable
-{
-    public abstract void dispose();
-}
diff --git a/src/api/java/IntNum.java b/src/api/java/IntNum.java
index 71d878311..d3a5b456f 100644
--- a/src/api/java/IntNum.java
+++ b/src/api/java/IntNum.java
@@ -63,14 +63,7 @@ public class IntNum extends IntExpr
     /**
      * Returns a string representation of the numeral.
      **/
-    public String toString()
-    {
-        try
-        {
-            return Native.getNumeralString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.getNumeralString(getContext().nCtx(), getNativeObject());
     }
 }
diff --git a/src/api/java/InterpolationContext.java b/src/api/java/InterpolationContext.java
index 47a128643..99a63821f 100644
--- a/src/api/java/InterpolationContext.java
+++ b/src/api/java/InterpolationContext.java
@@ -17,11 +17,10 @@ Notes:
 
 package com.microsoft.z3;
 
-import java.util.Map;
-import java.lang.String;
-
 import com.microsoft.z3.enumerations.Z3_lbool;
 
+import java.util.Map;
+
 /** 
  *  The InterpolationContext is suitable for generation of interpolants.
  *
@@ -33,13 +32,13 @@ public class InterpolationContext extends Context
     /**
      * Constructor.
      **/
-    public InterpolationContext()
+    public static InterpolationContext mkContext()
     {
-        super();
+        long m_ctx;
         synchronized(creation_lock) {
             m_ctx = Native.mkInterpolationContext(0);
-            initContext(); 
         }
+        return new InterpolationContext(m_ctx);
     }
 
     /** 
@@ -49,17 +48,21 @@ public class InterpolationContext extends Context
      * Remarks: 
      * @see Context#Context
      **/
-    public InterpolationContext(Map<String, String> settings)
+    public static InterpolationContext mkContext(Map<String, String> settings)
     { 
-        super();
+        long m_ctx;
         synchronized(creation_lock) {
             long cfg = Native.mkConfig();
             for (Map.Entry<String, String> kv : settings.entrySet())
                 Native.setParamValue(cfg, kv.getKey(), kv.getValue());
             m_ctx = Native.mkInterpolationContext(cfg);
             Native.delConfig(cfg);
-            initContext();
         }
+        return new InterpolationContext(m_ctx);
+    }
+
+    private InterpolationContext(long m_ctx) {
+        super(m_ctx);
     }
 
     /** 
diff --git a/src/api/java/ListSort.java b/src/api/java/ListSort.java
index 705e93579..0ff2c36cf 100644
--- a/src/api/java/ListSort.java
+++ b/src/api/java/ListSort.java
@@ -17,6 +17,8 @@ Notes:
 
 package com.microsoft.z3;
 
+import com.microsoft.z3.Native.LongPtr;
+
 /**
  * List sorts.
  **/
@@ -88,14 +90,9 @@ public class ListSort extends Sort
 
     ListSort(Context ctx, Symbol name, Sort elemSort)
     {
-        super(ctx, 0);
-
-        Native.LongPtr inil = new Native.LongPtr(), iisnil = new Native.LongPtr();
-        Native.LongPtr icons = new Native.LongPtr(), iiscons = new Native.LongPtr();
-        Native.LongPtr ihead = new Native.LongPtr(), itail = new Native.LongPtr();
-
-        setNativeObject(Native.mkListSort(ctx.nCtx(), name.getNativeObject(),
-                elemSort.getNativeObject(), inil, iisnil, icons, iiscons, ihead,
-                itail));
+        super(ctx, Native.mkListSort(ctx.nCtx(), name.getNativeObject(),
+                elemSort.getNativeObject(),
+                new LongPtr(), new Native.LongPtr(), new LongPtr(),
+                new LongPtr(), new LongPtr(), new LongPtr()));
     }
 };
diff --git a/src/api/java/Model.java b/src/api/java/Model.java
index 0695d7cf1..60abb001d 100644
--- a/src/api/java/Model.java
+++ b/src/api/java/Model.java
@@ -22,8 +22,7 @@ import com.microsoft.z3.enumerations.Z3_sort_kind;
 /**
  * A Model contains interpretations (assignments) of constants and functions.
  **/
-public class Model extends Z3Object
-{
+public class Model extends Z3Object {
     /**
      * Retrieves the interpretation (the assignment) of {@code a} in
      * the model. 
@@ -283,15 +282,8 @@ public class Model extends Z3Object
      * @return A string representation of the model.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.modelToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.modelToString(getContext().nCtx(), getNativeObject());
     }
 
     Model(Context ctx, long obj)
@@ -300,16 +292,12 @@ public class Model extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getModelDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.modelIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getModelDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getModelDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ModelDecRefQueue.java b/src/api/java/ModelDecRefQueue.java
index b97add310..f1b7c3fdd 100644
--- a/src/api/java/ModelDecRefQueue.java
+++ b/src/api/java/ModelDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class ModelDecRefQueue extends IDecRefQueue
-{
+class ModelDecRefQueue extends IDecRefQueue<Model> {
     public ModelDecRefQueue() 
     {
         super();
     }
 
-    public ModelDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.modelIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.modelDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.modelDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/Optimize.java b/src/api/java/Optimize.java
index 5dfe8fcf4..ea100d1ca 100644
--- a/src/api/java/Optimize.java
+++ b/src/api/java/Optimize.java
@@ -266,17 +266,12 @@ public class Optimize extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getOptimizeDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.optimizeIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getOptimizeDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getOptimizeDRQ().storeReference(getContext(), this);
     }
-
 }
diff --git a/src/api/java/OptimizeDecRefQueue.java b/src/api/java/OptimizeDecRefQueue.java
index 795a8a399..0acf20068 100644
--- a/src/api/java/OptimizeDecRefQueue.java
+++ b/src/api/java/OptimizeDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class OptimizeDecRefQueue extends IDecRefQueue
-{
+class OptimizeDecRefQueue extends IDecRefQueue<Optimize> {
     public OptimizeDecRefQueue() 
     {
         super();
     }
 
-    public OptimizeDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.fixedpointIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.fixedpointDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.optimizeDecRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/ParamDescrs.java b/src/api/java/ParamDescrs.java
index 8f8c6df0b..0008515e3 100644
--- a/src/api/java/ParamDescrs.java
+++ b/src/api/java/ParamDescrs.java
@@ -22,8 +22,7 @@ import com.microsoft.z3.enumerations.Z3_param_kind;
 /**
  * A ParamDescrs describes a set of parameters.
  **/
-public class ParamDescrs extends Z3Object
-{
+public class ParamDescrs extends Z3Object {
     /**
      * validate a set of parameters.
      **/
@@ -82,15 +81,8 @@ public class ParamDescrs extends Z3Object
      * Retrieves a string representation of the ParamDescrs.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.paramDescrsToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.paramDescrsToString(getContext().nCtx(), getNativeObject());
     }
 
     ParamDescrs(Context ctx, long obj)
@@ -99,16 +91,12 @@ public class ParamDescrs extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getParamDescrsDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.paramDescrsIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getParamDescrsDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getParamDescrsDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ParamDescrsDecRefQueue.java b/src/api/java/ParamDescrsDecRefQueue.java
index e3515bff6..ee3257db9 100644
--- a/src/api/java/ParamDescrsDecRefQueue.java
+++ b/src/api/java/ParamDescrsDecRefQueue.java
@@ -17,39 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class ParamDescrsDecRefQueue extends IDecRefQueue
-{
+class ParamDescrsDecRefQueue extends IDecRefQueue<ParamDescrs> {
     public ParamDescrsDecRefQueue() 
     {
         super();
     }
 
-    public ParamDescrsDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
-    @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.paramDescrsIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
     @Override
     protected void decRef(Context ctx, long obj)
     {
-        try
-        {
-            Native.paramDescrsDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+        Native.paramDescrsDecRef(ctx.nCtx(), obj);
     }
-};
+}
diff --git a/src/api/java/Params.java b/src/api/java/Params.java
index 25d009b12..a76dd3cab 100644
--- a/src/api/java/Params.java
+++ b/src/api/java/Params.java
@@ -21,8 +21,7 @@ package com.microsoft.z3;
 /**
  * A ParameterSet represents a configuration in the form of Symbol/value pairs.
  **/
-public class Params extends Z3Object
-{
+public class Params extends Z3Object {
     /**
      * Adds a parameter setting.
      **/
@@ -115,13 +114,7 @@ public class Params extends Z3Object
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.paramsToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.paramsToString(getContext().nCtx(), getNativeObject());
     }
 
     Params(Context ctx)
@@ -129,17 +122,14 @@ public class Params extends Z3Object
         super(ctx, Native.mkParams(ctx.nCtx()));
     }
 
+
     @Override
-    void incRef(long o)
-    {
-        getContext().getParamsDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.paramsIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getParamsDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getParamsDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ParamsDecRefQueue.java b/src/api/java/ParamsDecRefQueue.java
index f989f8015..349713f67 100644
--- a/src/api/java/ParamsDecRefQueue.java
+++ b/src/api/java/ParamsDecRefQueue.java
@@ -17,39 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class ParamsDecRefQueue extends IDecRefQueue
-{
+class ParamsDecRefQueue extends IDecRefQueue<Params> {
     public ParamsDecRefQueue() 
     {
         super();
     }
 
-    public ParamsDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.paramsIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.paramsDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.paramsDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/Pattern.java b/src/api/java/Pattern.java
index eb12b6448..852ffcd0f 100644
--- a/src/api/java/Pattern.java
+++ b/src/api/java/Pattern.java
@@ -53,13 +53,7 @@ public class Pattern extends AST
     @Override
     public String toString()
     {
-        try
-        {
-            return Native.patternToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.patternToString(getContext().nCtx(), getNativeObject());
     }
 
     Pattern(Context ctx, long obj)
diff --git a/src/api/java/Probe.java b/src/api/java/Probe.java
index bcaa76ce6..a36f3b64b 100644
--- a/src/api/java/Probe.java
+++ b/src/api/java/Probe.java
@@ -25,8 +25,7 @@ package com.microsoft.z3;
  * also be obtained using the command {@code (help-tactic)} in the SMT 2.0
  * front-end.
  **/
-public class Probe extends Z3Object
-{
+public class Probe extends Z3Object {
     /**
      * Execute the probe over the goal.
      * 
@@ -46,22 +45,17 @@ public class Probe extends Z3Object
         super(ctx, obj);
     }
 
-    Probe(Context ctx, String name)
-    {
+    Probe(Context ctx, String name) {
         super(ctx, Native.mkProbe(ctx.nCtx(), name));
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getProbeDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.probeIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getProbeDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getProbeDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/ProbeDecRefQueue.java b/src/api/java/ProbeDecRefQueue.java
index 368bd5bba..b25446c0c 100644
--- a/src/api/java/ProbeDecRefQueue.java
+++ b/src/api/java/ProbeDecRefQueue.java
@@ -17,39 +17,16 @@ Notes:
 
 package com.microsoft.z3;
 
-class ProbeDecRefQueue extends IDecRefQueue
+class ProbeDecRefQueue extends IDecRefQueue<Probe>
 {
     public ProbeDecRefQueue() 
     {
         super();
     }
 
-    public ProbeDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
-    @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.probeIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
     @Override
     protected void decRef(Context ctx, long obj)
     {
-        try
-        {
-            Native.probeDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+        Native.probeDecRef(ctx.nCtx(), obj);
     }
 };
diff --git a/src/api/java/Quantifier.java b/src/api/java/Quantifier.java
index 1b425d3e4..a78277839 100644
--- a/src/api/java/Quantifier.java
+++ b/src/api/java/Quantifier.java
@@ -145,68 +145,67 @@ public class Quantifier extends BoolExpr
                 .nCtx(), getNativeObject()));
     }
 
-    Quantifier(Context ctx, boolean isForall, Sort[] sorts, Symbol[] names,
+    public static Quantifier of(
+            Context ctx, boolean isForall, Sort[] sorts, Symbol[] names,
             Expr body, int weight, Pattern[] patterns, Expr[] noPatterns,
-            Symbol quantifierID, Symbol skolemID)
-    {
-        super(ctx, 0);
-
-        getContext().checkContextMatch(patterns);
-        getContext().checkContextMatch(noPatterns);
-        getContext().checkContextMatch(sorts);
-        getContext().checkContextMatch(names);
-        getContext().checkContextMatch(body);
+            Symbol quantifierID, Symbol skolemID
+    ) {
+        ctx.checkContextMatch(patterns);
+        ctx.checkContextMatch(noPatterns);
+        ctx.checkContextMatch(sorts);
+        ctx.checkContextMatch(names);
+        ctx.checkContextMatch(body);
 
         if (sorts.length != names.length)
             throw new Z3Exception(
                     "Number of sorts does not match number of names");
 
-        if (noPatterns == null && quantifierID == null && skolemID == null)
-        {
-            setNativeObject(Native.mkQuantifier(ctx.nCtx(), (isForall), weight, AST.arrayLength(patterns), AST
+        long nativeObj;
+        if (noPatterns == null && quantifierID == null && skolemID == null) {
+            nativeObj = Native.mkQuantifier(ctx.nCtx(), (isForall), weight, AST.arrayLength(patterns), AST
                     .arrayToNative(patterns), AST.arrayLength(sorts), AST
                     .arrayToNative(sorts), Symbol.arrayToNative(names), body
-                    .getNativeObject()));
-        } else
-        {
-            setNativeObject(Native.mkQuantifierEx(ctx.nCtx(),
-                (isForall), weight, AST.getNativeObject(quantifierID),
-             AST.getNativeObject(skolemID), 
-             AST.arrayLength(patterns), AST.arrayToNative(patterns), 
-             AST.arrayLength(noPatterns), AST.arrayToNative(noPatterns), 
-             AST.arrayLength(sorts), AST.arrayToNative(sorts), 
-             Symbol.arrayToNative(names), 
-             body.getNativeObject()));
+                    .getNativeObject());
+        } else {
+            nativeObj = Native.mkQuantifierEx(ctx.nCtx(),
+                    (isForall), weight, AST.getNativeObject(quantifierID),
+                    AST.getNativeObject(skolemID),
+                    AST.arrayLength(patterns), AST.arrayToNative(patterns),
+                    AST.arrayLength(noPatterns), AST.arrayToNative(noPatterns),
+                    AST.arrayLength(sorts), AST.arrayToNative(sorts),
+                    Symbol.arrayToNative(names),
+                    body.getNativeObject());
         }
+        return new Quantifier(ctx, nativeObj);
     }
 
-    Quantifier(Context ctx, boolean isForall, Expr[] bound, Expr body,
+
+    public static Quantifier of(Context ctx, boolean isForall, Expr[] bound, Expr body,
             int weight, Pattern[] patterns, Expr[] noPatterns,
             Symbol quantifierID, Symbol skolemID)
     {
-        super(ctx, 0);
-
-        getContext().checkContextMatch(noPatterns);
-        getContext().checkContextMatch(patterns);
-        // Context().CheckContextMatch(bound);
-        getContext().checkContextMatch(body);
+        ctx.checkContextMatch(noPatterns);
+        ctx.checkContextMatch(patterns);
+        // ctx.CheckContextMatch(bound);
+        ctx.checkContextMatch(body);
 
+        long nativeObj;
         if (noPatterns == null && quantifierID == null && skolemID == null)
         {
-            setNativeObject(Native.mkQuantifierConst(ctx.nCtx(),
+            nativeObj = Native.mkQuantifierConst(ctx.nCtx(),
                 isForall, weight, AST.arrayLength(bound),
                     AST.arrayToNative(bound), AST.arrayLength(patterns),
-                    AST.arrayToNative(patterns), body.getNativeObject()));
-        } else
-        {
-            setNativeObject(Native.mkQuantifierConstEx(ctx.nCtx(),
+                    AST.arrayToNative(patterns), body.getNativeObject());
+        } else {
+            nativeObj = Native.mkQuantifierConstEx(ctx.nCtx(),
                 isForall, weight,
                     AST.getNativeObject(quantifierID),
                     AST.getNativeObject(skolemID), AST.arrayLength(bound),
                     AST.arrayToNative(bound), AST.arrayLength(patterns),
                     AST.arrayToNative(patterns), AST.arrayLength(noPatterns),
-                    AST.arrayToNative(noPatterns), body.getNativeObject()));
+                    AST.arrayToNative(noPatterns), body.getNativeObject());
         }
+        return new Quantifier(ctx, nativeObj);
     }
 
     Quantifier(Context ctx, long obj)
diff --git a/src/api/java/RatNum.java b/src/api/java/RatNum.java
index f44823a2b..2bf1b28dd 100644
--- a/src/api/java/RatNum.java
+++ b/src/api/java/RatNum.java
@@ -75,15 +75,8 @@ public class RatNum extends RealExpr
      * Returns a string representation of the numeral.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            return Native.getNumeralString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    public String toString() {
+        return Native.getNumeralString(getContext().nCtx(), getNativeObject());
     }
 
     RatNum(Context ctx, long obj)
diff --git a/src/api/java/Solver.java b/src/api/java/Solver.java
index ea76637c8..a98fcbf94 100644
--- a/src/api/java/Solver.java
+++ b/src/api/java/Solver.java
@@ -22,8 +22,7 @@ import com.microsoft.z3.enumerations.Z3_lbool;
 /**
  * Solvers.
  **/
-public class Solver extends Z3Object
-{
+public class Solver extends Z3Object {
     /**
      * A string that describes all available solver parameters.
      **/
@@ -127,13 +126,13 @@ public class Solver extends Z3Object
      * using the Boolean constants in ps.
      *
      * Remarks: 
-     * This API is an alternative to {@link check} with assumptions for
+     * This API is an alternative to {@link #check()} with assumptions for
      * extracting unsat cores.
      * Both APIs can be used in the same solver. The unsat core will contain a
      * combination
-     * of the Boolean variables provided using {@link assertAndTrack}
+     * of the Boolean variables provided using {@code #assertAndTrack}
      * and the Boolean literals
-     * provided using {@link check} with assumptions.
+     * provided using {@link #check()} with assumptions.
      **/
     public void assertAndTrack(BoolExpr[] constraints, BoolExpr[] ps)
     {
@@ -154,13 +153,13 @@ public class Solver extends Z3Object
      * using the Boolean constant p.
      * 
      * Remarks: 
-     * This API is an alternative to {@link check} with assumptions for
+     * This API is an alternative to {@link #check} with assumptions for
      * extracting unsat cores.
      * Both APIs can be used in the same solver. The unsat core will contain a
      * combination
-     * of the Boolean variables provided using {@link assertAndTrack}
+     * of the Boolean variables provided using {@link #assertAndTrack}
      * and the Boolean literals
-     * provided using {@link check} with assumptions.
+     * provided using {@link #check} with assumptions.
      */ 
     public void assertAndTrack(BoolExpr constraint, BoolExpr p)
     {
@@ -323,14 +322,8 @@ public class Solver extends Z3Object
     @Override
     public String toString()
     {
-        try
-        {
-            return Native
-                    .solverToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native
+                .solverToString(getContext().nCtx(), getNativeObject());
     }
 
     Solver(Context ctx, long obj)
@@ -339,16 +332,12 @@ public class Solver extends Z3Object
     }
 
     @Override
-    void incRef(long o)
-    {
-        getContext().getSolverDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    void incRef() {
+        Native.solverIncRef(getContext().nCtx(), getNativeObject());
     }
 
     @Override
-    void decRef(long o)
-    {
-        getContext().getSolverDRQ().add(o);
-        super.decRef(o);
+    void addToReferenceQueue() {
+        getContext().getSolverDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/SolverDecRefQueue.java b/src/api/java/SolverDecRefQueue.java
index f4d5fb139..efa15d939 100644
--- a/src/api/java/SolverDecRefQueue.java
+++ b/src/api/java/SolverDecRefQueue.java
@@ -17,36 +17,11 @@ Notes:
 
 package com.microsoft.z3;
 
-class SolverDecRefQueue extends IDecRefQueue
-{
+class SolverDecRefQueue extends IDecRefQueue<Solver> {
     public SolverDecRefQueue() { super(); }
     
-    public SolverDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
     @Override
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.solverIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+    protected void decRef(Context ctx, long obj) {
+        Native.solverDecRef(ctx.nCtx(), obj);
     }
-
-    @Override
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.solverDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/Sort.java b/src/api/java/Sort.java
index e30e0b8b3..0763a69a3 100644
--- a/src/api/java/Sort.java
+++ b/src/api/java/Sort.java
@@ -82,15 +82,9 @@ public class Sort extends AST
     /**
      * A string representation of the sort.
      **/
-    public String toString()
-    {
-        try
-        {
-            return Native.sortToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+    @Override
+    public String toString() {
+        return Native.sortToString(getContext().nCtx(), getNativeObject());
     }
 
     /**
@@ -101,6 +95,7 @@ public class Sort extends AST
         super(ctx, obj);
     }
 
+    @Override
     void checkNativeObject(long obj)
     {
         if (Native.getAstKind(getContext().nCtx(), obj) != Z3_ast_kind.Z3_SORT_AST
diff --git a/src/api/java/Statistics.java b/src/api/java/Statistics.java
index 5af0cf863..356cbeadb 100644
--- a/src/api/java/Statistics.java
+++ b/src/api/java/Statistics.java
@@ -20,8 +20,7 @@ package com.microsoft.z3;
 /**
  * Objects of this class track statistical information about solvers.
  **/
-public class Statistics extends Z3Object
-{
+public class Statistics extends Z3Object {
     /**
      * Statistical data is organized into pairs of [Key, Entry], where every
      * Entry is either a {@code DoubleEntry} or a {@code UIntEntry}
@@ -84,15 +83,9 @@ public class Statistics extends Z3Object
         /**
          * The string representation of the Entry.
          **/
-        public String toString()
-        {
-            try
-            {
-                return Key + ": " + getValueString();
-            } catch (Z3Exception e)
-            {
-                return "Z3Exception: " + e.getMessage();
-            }
+        @Override
+        public String toString() {
+            return Key + ": " + getValueString();
         }
 
         private boolean m_is_int = false;
@@ -118,15 +111,10 @@ public class Statistics extends Z3Object
     /**
      * A string representation of the statistical data.
      **/
+    @Override
     public String toString()
     {
-        try
-        {
-            return Native.statsToString(getContext().nCtx(), getNativeObject());
-        } catch (Z3Exception e)
-        {
-            return "Z3Exception: " + e.getMessage();
-        }
+        return Native.statsToString(getContext().nCtx(), getNativeObject());
     }
 
     /**
@@ -201,15 +189,13 @@ public class Statistics extends Z3Object
         super(ctx, obj);
     }
 
-    void incRef(long o)
-    {
-        getContext().getStatisticsDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    @Override
+    void incRef() {
+        getContext().getStatisticsDRQ().storeReference(getContext(), this);
     }
 
-    void decRef(long o)
-    {
-        getContext().getStatisticsDRQ().add(o);
-        super.decRef(o);
+    @Override
+    void addToReferenceQueue() {
+        Native.statsIncRef(getContext().nCtx(), getNativeObject());
     }
 }
diff --git a/src/api/java/StatisticsDecRefQueue.java b/src/api/java/StatisticsDecRefQueue.java
index 89c66a746..ed698e4ca 100644
--- a/src/api/java/StatisticsDecRefQueue.java
+++ b/src/api/java/StatisticsDecRefQueue.java
@@ -17,37 +17,14 @@ Notes:
 
 package com.microsoft.z3;
 
-class StatisticsDecRefQueue extends IDecRefQueue
-{
+class StatisticsDecRefQueue extends IDecRefQueue<Statistics> {
     public StatisticsDecRefQueue() 
     {
         super();
     }
 
-    public StatisticsDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
+    @Override
+    protected void decRef(Context ctx, long obj) {
+        Native.statsDecRef(ctx.nCtx(), obj);
     }
-
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.statsIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
-    protected void decRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.statsDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-};
+}
diff --git a/src/api/java/StringSymbol.java b/src/api/java/StringSymbol.java
index 8470e1cd4..576737ea7 100644
--- a/src/api/java/StringSymbol.java
+++ b/src/api/java/StringSymbol.java
@@ -48,9 +48,9 @@ public class StringSymbol extends Symbol
     void checkNativeObject(long obj)
     {
         if (Native.getSymbolKind(getContext().nCtx(), obj) != Z3_symbol_kind.Z3_STRING_SYMBOL
-                .toInt())
+                .toInt()) {
             throw new Z3Exception("Symbol is not of String kind");
-
+        }
         super.checkNativeObject(obj);
     }
 }
diff --git a/src/api/java/Symbol.java b/src/api/java/Symbol.java
index beeaebb69..139894be1 100644
--- a/src/api/java/Symbol.java
+++ b/src/api/java/Symbol.java
@@ -22,8 +22,7 @@ import com.microsoft.z3.enumerations.Z3_symbol_kind;
 /**
  * Symbols are used to name several term and type constructors.
  **/
-public class Symbol extends Z3Object
-{
+public class Symbol extends Z3Object {
     /**
      * The kind of the symbol (int or string)
      **/
@@ -62,19 +61,13 @@ public class Symbol extends Z3Object
      * A string representation of the symbol.
      **/
     @Override
-    public String toString()
-    {
-        try
-        {
-            if (isIntSymbol())
-                return Integer.toString(((IntSymbol) this).getInt());
-            else if (isStringSymbol())
-                return ((StringSymbol) this).getString();
-            else
-                return "Z3Exception: Unknown symbol kind encountered.";
-        } catch (Z3Exception ex)
-        {
-            return "Z3Exception: " + ex.getMessage();
+    public String toString() {
+        if (isIntSymbol()) {
+            return Integer.toString(((IntSymbol) this).getInt());
+        } else if (isStringSymbol()) {
+            return ((StringSymbol) this).getString();
+        } else {
+            return "Z3Exception: Unknown symbol kind encountered.";
         }
     }
 
@@ -86,6 +79,17 @@ public class Symbol extends Z3Object
         super(ctx, obj);
     }
 
+    @Override
+    void incRef() {
+        // Symbol does not require tracking.
+    }
+
+    @Override
+    void addToReferenceQueue() {
+
+        // Symbol does not require tracking.
+    }
+
     static Symbol create(Context ctx, long obj)
     {
         switch (Z3_symbol_kind.fromInt(Native.getSymbolKind(ctx.nCtx(), obj)))
diff --git a/src/api/java/Tactic.java b/src/api/java/Tactic.java
index 786f8a6ec..11d02ca73 100644
--- a/src/api/java/Tactic.java
+++ b/src/api/java/Tactic.java
@@ -24,8 +24,7 @@ package com.microsoft.z3;
  * also be obtained using the command {@code (help-tactic)} in the SMT 2.0
  * front-end.
  **/
-public class Tactic extends Z3Object
-{
+public class Tactic extends Z3Object {
     /**
      * A string containing a description of parameters accepted by the tactic.
      **/
@@ -92,15 +91,13 @@ public class Tactic extends Z3Object
         super(ctx, Native.mkTactic(ctx.nCtx(), name));
     }
 
-    void incRef(long o)
-    {
-        getContext().getTacticDRQ().incAndClear(getContext(), o);
-        super.incRef(o);
+    @Override
+    void incRef() {
+        Native.tacticIncRef(getContext().nCtx(), getNativeObject());
     }
 
-    void decRef(long o)
-    {
-        getContext().getTacticDRQ().add(o);
-        super.decRef(o);
+    @Override
+    void addToReferenceQueue() {
+        getContext().getTacticDRQ().storeReference(getContext(), this);
     }
 }
diff --git a/src/api/java/TacticDecRefQueue.java b/src/api/java/TacticDecRefQueue.java
index 026760e46..8f151f25c 100644
--- a/src/api/java/TacticDecRefQueue.java
+++ b/src/api/java/TacticDecRefQueue.java
@@ -17,37 +17,15 @@ Notes:
 
 package com.microsoft.z3;
 
-class TacticDecRefQueue extends IDecRefQueue
-{
+class TacticDecRefQueue extends IDecRefQueue<Tactic> {
     public TacticDecRefQueue() 
     {
         super();
     }
 
-    public TacticDecRefQueue(int move_limit) 
-    {
-        super(move_limit);
-    }
-
-    protected void incRef(Context ctx, long obj)
-    {
-        try
-        {
-            Native.tacticIncRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
-    }
-
+    @Override
     protected void decRef(Context ctx, long obj)
     {
-        try
-        {
-            Native.tacticDecRef(ctx.nCtx(), obj);
-        } catch (Z3Exception e)
-        {
-            // OK.
-        }
+        Native.tacticDecRef(ctx.nCtx(), obj);
     }
-};
+}
diff --git a/src/api/java/TupleSort.java b/src/api/java/TupleSort.java
index 1594b874d..ede20d260 100644
--- a/src/api/java/TupleSort.java
+++ b/src/api/java/TupleSort.java
@@ -59,11 +59,9 @@ public class TupleSort extends Sort
     TupleSort(Context ctx, Symbol name, int numFields, Symbol[] fieldNames,
             Sort[] fieldSorts)
     {
-        super(ctx, 0);
-
-        Native.LongPtr t = new Native.LongPtr();
-        setNativeObject(Native.mkTupleSort(ctx.nCtx(), name.getNativeObject(),
+        super(ctx, Native.mkTupleSort(ctx.nCtx(), name.getNativeObject(),
                 numFields, Symbol.arrayToNative(fieldNames),
-                AST.arrayToNative(fieldSorts), t, new long[numFields]));
+                AST.arrayToNative(fieldSorts), new Native.LongPtr(),
+                new long[numFields]));
     }
 };
diff --git a/src/api/java/Z3Object.java b/src/api/java/Z3Object.java
index dc1feecbf..7c5f606d9 100644
--- a/src/api/java/Z3Object.java
+++ b/src/api/java/Z3Object.java
@@ -21,88 +21,43 @@ package com.microsoft.z3;
  * Internal base class for interfacing with native Z3 objects. Should not be
  * used externally.
  **/
-public class Z3Object extends IDisposable
-{
-    /**
-     * Finalizer.
-     * @throws Throwable 
-     **/
-    protected void finalize() throws Throwable
-    {
-        try {
-            dispose();            
-        } finally {
-            super.finalize();
-        }
-    }
+public abstract class Z3Object {
 
-    /**
-     * Disposes of the underlying native Z3 object.
-     **/
-    public void dispose()
-    {
-        if (m_n_obj != 0)
-        {
-            decRef(m_n_obj);
-            m_n_obj = 0;
-        }
+    private final Context m_ctx;
+    private final long m_n_obj;
 
-        if (m_ctx != null)
-        {            
-            if (m_ctx.m_refCount.decrementAndGet() == 0)
-                m_ctx.dispose();
-            m_ctx = null;
-        }
-    }
-
-    private Context m_ctx = null;
-    private long m_n_obj = 0;
-
-    Z3Object(Context ctx)
-    {
-        ctx.m_refCount.incrementAndGet();
+    Z3Object(Context ctx, long obj) {
         m_ctx = ctx;
-    }
-
-    Z3Object(Context ctx, long obj)
-    {
-        ctx.m_refCount.incrementAndGet();
-        m_ctx = ctx;
-        incRef(obj);
+        checkNativeObject(obj);
         m_n_obj = obj;
+        incRef();
+        addToReferenceQueue();
     }
 
-    void incRef(long o)
-    {
-    }
+    /**
+     * Add to ReferenceQueue for tracking reachability on the object and
+     * decreasing the reference count when the object is no longer reachable.
+     */
+    abstract void addToReferenceQueue();
 
-    void decRef(long o)
-    {
-    }
+    /**
+     * Increment reference count on {@code this}.
+     */
+    abstract void incRef();
 
-    void checkNativeObject(long obj)
-    {
-    }
+    /**
+     * This function is provided for overriding, and a child class
+     * can insert consistency checks on {@code obj}.
+     *
+     * @param obj Z3 native object.
+     */
+    void checkNativeObject(long obj) {}
 
     long getNativeObject()
     {
         return m_n_obj;
     }
 
-    void setNativeObject(long value)
-    {
-        if (value != 0)
-        {
-            checkNativeObject(value);
-            incRef(value);
-        }
-        if (m_n_obj != 0)
-        {
-            decRef(m_n_obj);
-        }
-        m_n_obj = value;
-    }
-
     static long getNativeObject(Z3Object s)
     {
         if (s == null)
@@ -121,7 +76,7 @@ public class Z3Object extends IDisposable
             return null;
         long[] an = new long[a.length];
         for (int i = 0; i < a.length; i++)
-        an[i] = (a[i] == null) ? 0 : a[i].getNativeObject();
+            an[i] = (a[i] == null) ? 0 : a[i].getNativeObject();
         return an;
     }
 
diff --git a/src/api/ml/z3native_stubs.c.pre b/src/api/ml/z3native_stubs.c.pre
index d6b2cdab4..5960d5095 100644
--- a/src/api/ml/z3native_stubs.c.pre
+++ b/src/api/ml/z3native_stubs.c.pre
@@ -227,6 +227,7 @@ void Z3_ast_finalize(value v) {
 int Z3_ast_compare(value v1, value v2) {
   Z3_ast_plus * a1 = (Z3_ast_plus*)Data_custom_val(v1);
   Z3_ast_plus * a2 = (Z3_ast_plus*)Data_custom_val(v2);
+  unsigned id1, id2;
 
   /* if the two ASTs belong to different contexts, we take
      their contexts' addresses to order them (arbitrarily, but fixed) */
@@ -242,8 +243,8 @@ int Z3_ast_compare(value v1, value v2) {
     return +1;
 
   /* Comparison according to AST ids. */
-  unsigned id1 = Z3_get_ast_id(a1->cp->ctx, a1->p);
-  unsigned id2 = Z3_get_ast_id(a2->cp->ctx, a2->p);
+  id1 = Z3_get_ast_id(a1->cp->ctx, a1->p);
+  id2 = Z3_get_ast_id(a2->cp->ctx, a2->p);
   if (id1 == id2)
     return 0;
   else if (id1 < id2)
@@ -255,7 +256,7 @@ int Z3_ast_compare(value v1, value v2) {
 int Z3_ast_compare_ext(value v1, value v2) {
   Z3_ast_plus * a1 = (Z3_ast_plus*)Data_custom_val(v1);
   unsigned id1;
-  int id2 = Val_int(v2);
+  unsigned id2 = (unsigned)Val_int(v2);
   if (a1->p == NULL && id2 == 0)
     return 0;
   if (a1->p == NULL)
diff --git a/src/ast/pattern/pattern_inference_params.cpp b/src/ast/pattern/pattern_inference_params.cpp
index 8adbdb9f1..b36d372f5 100644
--- a/src/ast/pattern/pattern_inference_params.cpp
+++ b/src/ast/pattern/pattern_inference_params.cpp
@@ -30,3 +30,18 @@ void pattern_inference_params::updt_params(params_ref const & _p) {
     m_pi_pull_quantifiers        = p.pull_quantifiers();
     m_pi_warnings                = p.warnings();
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void pattern_inference_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_pi_max_multi_patterns);
+    DISPLAY_PARAM(m_pi_block_loop_patterns);
+    DISPLAY_PARAM(m_pi_arith);
+    DISPLAY_PARAM(m_pi_use_database);
+    DISPLAY_PARAM(m_pi_arith_weight);
+    DISPLAY_PARAM(m_pi_non_nested_arith_weight);
+    DISPLAY_PARAM(m_pi_pull_quantifiers);
+    DISPLAY_PARAM(m_pi_nopat_weight);
+    DISPLAY_PARAM(m_pi_avoid_skolems);
+    DISPLAY_PARAM(m_pi_warnings);
+}
\ No newline at end of file
diff --git a/src/ast/pattern/pattern_inference_params.h b/src/ast/pattern/pattern_inference_params.h
index a941b7dd6..0dc413399 100644
--- a/src/ast/pattern/pattern_inference_params.h
+++ b/src/ast/pattern/pattern_inference_params.h
@@ -46,6 +46,8 @@ struct pattern_inference_params {
     }
 
     void updt_params(params_ref const & _p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* PATTERN_INFERENCE_PARAMS_H_ */
diff --git a/src/ast/rewriter/bit_blaster/bit_blaster_params.h b/src/ast/rewriter/bit_blaster/bit_blaster_params.h
index ee32d005a..15ece0043 100644
--- a/src/ast/rewriter/bit_blaster/bit_blaster_params.h
+++ b/src/ast/rewriter/bit_blaster/bit_blaster_params.h
@@ -22,7 +22,7 @@ Revision History:
 struct bit_blaster_params {
     bool  m_bb_ext_gates;
     bool  m_bb_quantifiers;
-    bit_blaster_params():
+    bit_blaster_params() :
         m_bb_ext_gates(false),
         m_bb_quantifiers(false) {
     }
@@ -32,6 +32,11 @@ struct bit_blaster_params {
         p.register_bool_param("bb_quantifiers", m_bb_quantifiers, "convert bit-vectors to Booleans in quantifiers");
     }
 #endif
+
+    void display(std::ostream & out) const {
+        out << "m_bb_ext_gates=" << m_bb_ext_gates << std::endl;
+        out << "m_bb_quantifiers=" << m_bb_quantifiers << std::endl;
+    }
 };
 
 #endif /* BIT_BLASTER_PARAMS_H_ */
diff --git a/src/ast/simplifier/arith_simplifier_params.cpp b/src/ast/simplifier/arith_simplifier_params.cpp
index a3fabe02f..8584cdae0 100644
--- a/src/ast/simplifier/arith_simplifier_params.cpp
+++ b/src/ast/simplifier/arith_simplifier_params.cpp
@@ -24,3 +24,10 @@ void arith_simplifier_params::updt_params(params_ref const & _p) {
     m_arith_expand_eqs      = p.arith_expand_eqs();
     m_arith_process_all_eqs = p.arith_process_all_eqs();
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void arith_simplifier_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_arith_expand_eqs);
+    DISPLAY_PARAM(m_arith_process_all_eqs);
+}
\ No newline at end of file
diff --git a/src/ast/simplifier/arith_simplifier_params.h b/src/ast/simplifier/arith_simplifier_params.h
index 2ff8fe2c0..6186ee4a2 100644
--- a/src/ast/simplifier/arith_simplifier_params.h
+++ b/src/ast/simplifier/arith_simplifier_params.h
@@ -30,6 +30,8 @@ struct arith_simplifier_params {
     }
 
     void updt_params(params_ref const & _p);
+
+    void display(std::ostream & out) const;
 };
     
 #endif /* ARITH_SIMPLIFIER_PARAMS_H_ */
diff --git a/src/ast/simplifier/bv_simplifier_params.cpp b/src/ast/simplifier/bv_simplifier_params.cpp
index 5d6cd363f..1ed263aa6 100644
--- a/src/ast/simplifier/bv_simplifier_params.cpp
+++ b/src/ast/simplifier/bv_simplifier_params.cpp
@@ -27,3 +27,10 @@ void bv_simplifier_params::updt_params(params_ref const & _p) {
     m_bv2int_distribute = p.bv_bv2int_distribute();
 
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void bv_simplifier_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_hi_div0);
+    DISPLAY_PARAM(m_bv2int_distribute);
+}
\ No newline at end of file
diff --git a/src/ast/simplifier/bv_simplifier_params.h b/src/ast/simplifier/bv_simplifier_params.h
index 50015b7ca..dafa99065 100644
--- a/src/ast/simplifier/bv_simplifier_params.h
+++ b/src/ast/simplifier/bv_simplifier_params.h
@@ -30,6 +30,8 @@ struct bv_simplifier_params {
     }
 
     void updt_params(params_ref const & _p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* BV_SIMPLIFIER_PARAMS_H_ */
diff --git a/src/opt/maxres.cpp b/src/opt/maxres.cpp
index b52c7d9b9..b6950f674 100644
--- a/src/opt/maxres.cpp
+++ b/src/opt/maxres.cpp
@@ -544,18 +544,11 @@ public:
             return l_true;
         }
         m_mus.reset();
-        for (unsigned i = 0; i < core.size(); ++i) {
-            VERIFY(i == m_mus.add_soft(core[i]));
-        }
-        unsigned_vector mus_idx;
-        lbool is_sat = m_mus.get_mus(mus_idx);
+        m_mus.add_soft(core.size(), core.c_ptr());
+        lbool is_sat = m_mus.get_mus(m_new_core);
         if (is_sat != l_true) {
             return is_sat;
         }
-        m_new_core.reset();
-        for (unsigned i = 0; i < mus_idx.size(); ++i) {
-            m_new_core.push_back(core[mus_idx[i]]);
-        }
         core.reset();
         core.append(m_new_core);
         return l_true;
diff --git a/src/qe/qsat.cpp b/src/qe/qsat.cpp
index 74b6769ae..02c6d26cd 100644
--- a/src/qe/qsat.cpp
+++ b/src/qe/qsat.cpp
@@ -811,14 +811,10 @@ namespace qe {
             }
             TRACE("qe", tout << core1.size() << " " << core2.size() << "\n";);
             if (core1.size() > 8) {
-                unsigned_vector core_idxs;
-                if (l_true != mus.get_mus(core_idxs)) {
+                if (l_true != mus.get_mus(core2)) {
                     return false;
                 }
-                TRACE("qe", tout << core1.size() << " -> " << core_idxs.size() << "\n";);
-                for (unsigned i = 0; i < core_idxs.size(); ++i) {
-                    core2.push_back(core1[core_idxs[i]].get());
-                }
+                TRACE("qe", tout << core1.size() << " -> " << core2.size() << "\n";);
                 core.reset();
                 core.append(core2);
             }
diff --git a/src/smt/params/dyn_ack_params.cpp b/src/smt/params/dyn_ack_params.cpp
index 15f48bad1..b62530fbf 100644
--- a/src/smt/params/dyn_ack_params.cpp
+++ b/src/smt/params/dyn_ack_params.cpp
@@ -28,3 +28,14 @@ void dyn_ack_params::updt_params(params_ref const & _p) {
     m_dack_gc = p.dack_gc();
     m_dack_gc_inv_decay = p.dack_gc_inv_decay();
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void dyn_ack_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_dack);
+    DISPLAY_PARAM(m_dack_eq);
+    DISPLAY_PARAM(m_dack_factor);
+    DISPLAY_PARAM(m_dack_threshold);
+    DISPLAY_PARAM(m_dack_gc);
+    DISPLAY_PARAM(m_dack_gc_inv_decay);
+}
\ No newline at end of file
diff --git a/src/smt/params/dyn_ack_params.h b/src/smt/params/dyn_ack_params.h
index f87e3b6df..017b7fe94 100644
--- a/src/smt/params/dyn_ack_params.h
+++ b/src/smt/params/dyn_ack_params.h
@@ -47,6 +47,8 @@ public:
     }
 
     void updt_params(params_ref const & _p);
+
+    void display(std::ostream & out) const;
 };
 
 
diff --git a/src/smt/params/preprocessor_params.cpp b/src/smt/params/preprocessor_params.cpp
index 9ad787c2a..7a0e96248 100644
--- a/src/smt/params/preprocessor_params.cpp
+++ b/src/smt/params/preprocessor_params.cpp
@@ -32,3 +32,33 @@ void preprocessor_params::updt_params(params_ref const & p) {
     arith_simplifier_params::updt_params(p);
     updt_local_params(p);
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void preprocessor_params::display(std::ostream & out) const {
+    pattern_inference_params::display(out);
+    bit_blaster_params::display(out);
+    bv_simplifier_params::display(out);
+    arith_simplifier_params::display(out);
+
+    DISPLAY_PARAM(m_lift_ite);
+    DISPLAY_PARAM(m_ng_lift_ite);
+    DISPLAY_PARAM(m_pull_cheap_ite_trees);
+    DISPLAY_PARAM(m_pull_nested_quantifiers);
+    DISPLAY_PARAM(m_eliminate_term_ite);
+    DISPLAY_PARAM(m_eliminate_and);
+    DISPLAY_PARAM(m_macro_finder);
+    DISPLAY_PARAM(m_propagate_values);
+    DISPLAY_PARAM(m_propagate_booleans);
+    DISPLAY_PARAM(m_refine_inj_axiom);
+    DISPLAY_PARAM(m_eliminate_bounds);
+    DISPLAY_PARAM(m_simplify_bit2int);
+    DISPLAY_PARAM(m_nnf_cnf);
+    DISPLAY_PARAM(m_distribute_forall);
+    DISPLAY_PARAM(m_reduce_args);
+    DISPLAY_PARAM(m_quasi_macros);
+    DISPLAY_PARAM(m_restricted_quasi_macros);
+    DISPLAY_PARAM(m_max_bv_sharing);
+    DISPLAY_PARAM(m_pre_simplifier);
+    DISPLAY_PARAM(m_nlquant_elim);
+}
diff --git a/src/smt/params/preprocessor_params.h b/src/smt/params/preprocessor_params.h
index 3806b26cf..4ffad48a2 100644
--- a/src/smt/params/preprocessor_params.h
+++ b/src/smt/params/preprocessor_params.h
@@ -83,6 +83,8 @@ public:
     void updt_local_params(params_ref const & p);
 
     void updt_params(params_ref const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* PREPROCESSOR_PARAMS_H_ */
diff --git a/src/smt/params/qi_params.cpp b/src/smt/params/qi_params.cpp
index 60fcd6fc4..a341040ce 100644
--- a/src/smt/params/qi_params.cpp
+++ b/src/smt/params/qi_params.cpp
@@ -36,3 +36,30 @@ void qi_params::updt_params(params_ref const & _p) {
     m_qi_cost = p.qi_cost();
     m_qi_max_eager_multipatterns = p.qi_max_multi_patterns();
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void qi_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_qi_ematching);
+    DISPLAY_PARAM(m_qi_cost);
+    DISPLAY_PARAM(m_qi_new_gen);
+    DISPLAY_PARAM(m_qi_eager_threshold);
+    DISPLAY_PARAM(m_qi_lazy_threshold);
+    DISPLAY_PARAM(m_qi_max_eager_multipatterns);
+    DISPLAY_PARAM(m_qi_max_lazy_multipattern_matching);
+    DISPLAY_PARAM(m_qi_profile);
+    DISPLAY_PARAM(m_qi_profile_freq);
+    DISPLAY_PARAM(m_qi_quick_checker);
+    DISPLAY_PARAM(m_qi_lazy_quick_checker);
+    DISPLAY_PARAM(m_qi_promote_unsat);
+    DISPLAY_PARAM(m_qi_max_instances);
+    DISPLAY_PARAM(m_qi_lazy_instantiation);
+    DISPLAY_PARAM(m_qi_conservative_final_check);
+    DISPLAY_PARAM(m_mbqi);
+    DISPLAY_PARAM(m_mbqi_max_cexs);
+    DISPLAY_PARAM(m_mbqi_max_cexs_incr);
+    DISPLAY_PARAM(m_mbqi_max_iterations);
+    DISPLAY_PARAM(m_mbqi_trace);
+    DISPLAY_PARAM(m_mbqi_force_template);
+    DISPLAY_PARAM(m_mbqi_id);
+}
\ No newline at end of file
diff --git a/src/smt/params/qi_params.h b/src/smt/params/qi_params.h
index 00baea170..c9736909a 100644
--- a/src/smt/params/qi_params.h
+++ b/src/smt/params/qi_params.h
@@ -98,13 +98,15 @@ struct qi_params {
         m_mbqi_max_cexs_incr(1),
         m_mbqi_max_iterations(1000),
         m_mbqi_trace(false),
-	m_mbqi_force_template(10),
+        m_mbqi_force_template(10),
         m_mbqi_id(0)  
     {
         updt_params(p);
     }
 
     void updt_params(params_ref const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* QI_PARAMS_H_ */
diff --git a/src/smt/params/smt_params.cpp b/src/smt/params/smt_params.cpp
index 8222c3d60..8a9188e2b 100644
--- a/src/smt/params/smt_params.cpp
+++ b/src/smt/params/smt_params.cpp
@@ -63,3 +63,96 @@ void smt_params::updt_params(context_params const & p) {
     m_auto_config    = p.m_auto_config;
     m_model          = p.m_model;
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void smt_params::display(std::ostream & out) const {
+    preprocessor_params::display(out);
+    dyn_ack_params::display(out);
+    qi_params::display(out);
+    theory_arith_params::display(out);
+    theory_array_params::display(out);
+    theory_bv_params::display(out);
+    theory_pb_params::display(out);
+    theory_datatype_params::display(out);
+
+    DISPLAY_PARAM(m_display_proof);
+    DISPLAY_PARAM(m_display_dot_proof);
+    DISPLAY_PARAM(m_display_unsat_core);
+    DISPLAY_PARAM(m_check_proof);
+    DISPLAY_PARAM(m_eq_propagation);
+    DISPLAY_PARAM(m_binary_clause_opt);
+    DISPLAY_PARAM(m_relevancy_lvl);
+    DISPLAY_PARAM(m_relevancy_lemma);
+    DISPLAY_PARAM(m_random_seed);
+    DISPLAY_PARAM(m_random_var_freq);
+    DISPLAY_PARAM(m_inv_decay);
+    DISPLAY_PARAM(m_clause_decay);
+    DISPLAY_PARAM(m_random_initial_activity);
+    DISPLAY_PARAM(m_phase_selection);
+    DISPLAY_PARAM(m_phase_caching_on);
+    DISPLAY_PARAM(m_phase_caching_off);
+    DISPLAY_PARAM(m_minimize_lemmas);
+    DISPLAY_PARAM(m_max_conflicts);
+    DISPLAY_PARAM(m_simplify_clauses);
+    DISPLAY_PARAM(m_tick);
+    DISPLAY_PARAM(m_display_features);
+    DISPLAY_PARAM(m_new_core2th_eq);
+    DISPLAY_PARAM(m_ematching);
+
+    DISPLAY_PARAM(m_case_split_strategy);
+    DISPLAY_PARAM(m_rel_case_split_order);
+    DISPLAY_PARAM(m_lookahead_diseq);
+
+    DISPLAY_PARAM(m_delay_units);
+    DISPLAY_PARAM(m_delay_units_threshold);
+
+    DISPLAY_PARAM(m_theory_resolve);
+
+    DISPLAY_PARAM(m_restart_strategy);
+    DISPLAY_PARAM(m_restart_initial);
+    DISPLAY_PARAM(m_restart_factor);
+    DISPLAY_PARAM(m_restart_adaptive);
+    DISPLAY_PARAM(m_agility_factor);
+    DISPLAY_PARAM(m_restart_agility_threshold);
+
+    DISPLAY_PARAM(m_lemma_gc_strategy);
+    DISPLAY_PARAM(m_lemma_gc_half);
+    DISPLAY_PARAM(m_recent_lemmas_size);
+    DISPLAY_PARAM(m_lemma_gc_initial);
+    DISPLAY_PARAM(m_lemma_gc_factor);
+    DISPLAY_PARAM(m_new_old_ratio);
+    DISPLAY_PARAM(m_new_clause_activity);
+    DISPLAY_PARAM(m_old_clause_activity);
+    DISPLAY_PARAM(m_new_clause_relevancy);
+    DISPLAY_PARAM(m_old_clause_relevancy);
+    DISPLAY_PARAM(m_inv_clause_decay);
+
+    DISPLAY_PARAM(m_smtlib_dump_lemmas);
+    DISPLAY_PARAM(m_logic);
+
+    DISPLAY_PARAM(m_profile_res_sub);
+    DISPLAY_PARAM(m_display_bool_var2expr);
+    DISPLAY_PARAM(m_display_ll_bool_var2expr);
+    DISPLAY_PARAM(m_abort_after_preproc);
+
+    DISPLAY_PARAM(m_model);
+    DISPLAY_PARAM(m_model_compact);
+    DISPLAY_PARAM(m_model_on_timeout);
+    DISPLAY_PARAM(m_model_on_final_check);
+
+    DISPLAY_PARAM(m_progress_sampling_freq);
+
+    DISPLAY_PARAM(m_display_installed_theories);
+    DISPLAY_PARAM(m_core_validate);
+
+    DISPLAY_PARAM(m_preprocess);
+    DISPLAY_PARAM(m_user_theory_preprocess_axioms);
+    DISPLAY_PARAM(m_user_theory_persist_axioms);
+    DISPLAY_PARAM(m_timeout);
+    DISPLAY_PARAM(m_rlimit);
+    DISPLAY_PARAM(m_at_labels_cex);
+    DISPLAY_PARAM(m_check_at_labels);
+    DISPLAY_PARAM(m_dump_goal_as_smt);
+    DISPLAY_PARAM(m_auto_config);
+}
\ No newline at end of file
diff --git a/src/smt/params/smt_params.h b/src/smt/params/smt_params.h
index 9c1eec649..366570365 100644
--- a/src/smt/params/smt_params.h
+++ b/src/smt/params/smt_params.h
@@ -289,6 +289,8 @@ struct smt_params : public preprocessor_params,
     void updt_params(params_ref const & p);
 
     void updt_params(context_params const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* SMT_PARAMS_H_ */
diff --git a/src/smt/params/theory_arith_params.cpp b/src/smt/params/theory_arith_params.cpp
index fef7ca2a0..1e3f29142 100644
--- a/src/smt/params/theory_arith_params.cpp
+++ b/src/smt/params/theory_arith_params.cpp
@@ -38,3 +38,51 @@ void theory_arith_params::updt_params(params_ref const & _p) {
 }
 
 
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void theory_arith_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_arith_mode);
+    DISPLAY_PARAM(m_arith_auto_config_simplex); //!< force simplex solver in auto_config
+    DISPLAY_PARAM(m_arith_blands_rule_threshold);
+    DISPLAY_PARAM(m_arith_propagate_eqs);
+    DISPLAY_PARAM(m_arith_bound_prop);
+    DISPLAY_PARAM(m_arith_stronger_lemmas);
+    DISPLAY_PARAM(m_arith_skip_rows_with_big_coeffs);
+    DISPLAY_PARAM(m_arith_max_lemma_size);
+    DISPLAY_PARAM(m_arith_small_lemma_size);
+    DISPLAY_PARAM(m_arith_reflect);
+    DISPLAY_PARAM(m_arith_ignore_int);
+    DISPLAY_PARAM(m_arith_lazy_pivoting_lvl);
+    DISPLAY_PARAM(m_arith_random_seed);
+    DISPLAY_PARAM(m_arith_random_initial_value);
+    DISPLAY_PARAM(m_arith_random_lower);
+    DISPLAY_PARAM(m_arith_random_upper);
+    DISPLAY_PARAM(m_arith_adaptive);
+    DISPLAY_PARAM(m_arith_adaptive_assertion_threshold);
+    DISPLAY_PARAM(m_arith_adaptive_propagation_threshold);
+    DISPLAY_PARAM(m_arith_dump_lemmas);
+    DISPLAY_PARAM(m_arith_eager_eq_axioms);
+    DISPLAY_PARAM(m_arith_branch_cut_ratio);
+    DISPLAY_PARAM(m_arith_int_eq_branching);
+    DISPLAY_PARAM(m_arith_enum_const_mod);
+    DISPLAY_PARAM(m_arith_gcd_test);
+    DISPLAY_PARAM(m_arith_eager_gcd);
+    DISPLAY_PARAM(m_arith_adaptive_gcd);
+    DISPLAY_PARAM(m_arith_propagation_threshold);
+    DISPLAY_PARAM(m_arith_pivot_strategy);
+    DISPLAY_PARAM(m_arith_add_binary_bounds);
+    DISPLAY_PARAM(m_arith_propagation_strategy);
+    DISPLAY_PARAM(m_arith_eq_bounds);
+    DISPLAY_PARAM(m_arith_lazy_adapter);
+    DISPLAY_PARAM(m_arith_fixnum);
+    DISPLAY_PARAM(m_arith_int_only);
+    DISPLAY_PARAM(m_nl_arith);
+    DISPLAY_PARAM(m_nl_arith_gb);
+    DISPLAY_PARAM(m_nl_arith_gb_threshold);
+    DISPLAY_PARAM(m_nl_arith_gb_eqs);
+    DISPLAY_PARAM(m_nl_arith_gb_perturbate);
+    DISPLAY_PARAM(m_nl_arith_max_degree);
+    DISPLAY_PARAM(m_nl_arith_branching);
+    DISPLAY_PARAM(m_nl_arith_rounds);
+    DISPLAY_PARAM(m_arith_euclidean_solver);
+}
\ No newline at end of file
diff --git a/src/smt/params/theory_arith_params.h b/src/smt/params/theory_arith_params.h
index 18418d1ef..943bd711e 100644
--- a/src/smt/params/theory_arith_params.h
+++ b/src/smt/params/theory_arith_params.h
@@ -156,6 +156,8 @@ struct theory_arith_params {
     }
 
     void updt_params(params_ref const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* THEORY_ARITH_PARAMS_H_ */
diff --git a/src/smt/params/theory_array_params.cpp b/src/smt/params/theory_array_params.cpp
index e3c8b2448..c0015bf2c 100644
--- a/src/smt/params/theory_array_params.cpp
+++ b/src/smt/params/theory_array_params.cpp
@@ -25,4 +25,16 @@ void theory_array_params::updt_params(params_ref const & _p) {
     m_array_extensional = p.array_extensional();
 }
 
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
 
+void theory_array_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_array_mode);
+    DISPLAY_PARAM(m_array_weak);
+    DISPLAY_PARAM(m_array_extensional);
+    DISPLAY_PARAM(m_array_laziness);
+    DISPLAY_PARAM(m_array_delay_exp_axiom);
+    DISPLAY_PARAM(m_array_cg);
+    DISPLAY_PARAM(m_array_always_prop_upward);
+    DISPLAY_PARAM(m_array_lazy_ieq);
+    DISPLAY_PARAM(m_array_lazy_ieq_delay);
+}
\ No newline at end of file
diff --git a/src/smt/params/theory_array_params.h b/src/smt/params/theory_array_params.h
index 85996078f..af51427c4 100644
--- a/src/smt/params/theory_array_params.h
+++ b/src/smt/params/theory_array_params.h
@@ -71,6 +71,7 @@ struct theory_array_params : public array_simplifier_params {
     }
 #endif
 
+    void display(std::ostream & out) const;
 };
 
 
diff --git a/src/smt/params/theory_bv_params.cpp b/src/smt/params/theory_bv_params.cpp
index d3f386ab4..631c5765b 100644
--- a/src/smt/params/theory_bv_params.cpp
+++ b/src/smt/params/theory_bv_params.cpp
@@ -24,3 +24,14 @@ void theory_bv_params::updt_params(params_ref const & _p) {
     m_bv_reflect = p.bv_reflect();
     m_bv_enable_int2bv2int = p.bv_enable_int2bv(); 
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void theory_bv_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_bv_mode);
+    DISPLAY_PARAM(m_bv_reflect);
+    DISPLAY_PARAM(m_bv_lazy_le);
+    DISPLAY_PARAM(m_bv_cc);
+    DISPLAY_PARAM(m_bv_blast_max_size);
+    DISPLAY_PARAM(m_bv_enable_int2bv2int);
+}
\ No newline at end of file
diff --git a/src/smt/params/theory_bv_params.h b/src/smt/params/theory_bv_params.h
index 00565969e..5830e5176 100644
--- a/src/smt/params/theory_bv_params.h
+++ b/src/smt/params/theory_bv_params.h
@@ -44,6 +44,8 @@ struct theory_bv_params {
     }
     
     void updt_params(params_ref const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* THEORY_BV_PARAMS_H_ */
diff --git a/src/smt/params/theory_datatype_params.h b/src/smt/params/theory_datatype_params.h
index 4dd09a596..9f801e46c 100644
--- a/src/smt/params/theory_datatype_params.h
+++ b/src/smt/params/theory_datatype_params.h
@@ -31,6 +31,8 @@ struct theory_datatype_params {
         p.register_unsigned_param("dt_lazy_splits", m_dt_lazy_splits, "How lazy datatype splits are performed: 0- eager, 1- lazy for infinite types, 2- lazy");
     }
 #endif
+
+    void display(std::ostream & out) const { out << "m_dt_lazy_splits=" << m_dt_lazy_splits << std::endl; }
 };
 
 
diff --git a/src/smt/params/theory_pb_params.cpp b/src/smt/params/theory_pb_params.cpp
index 6d980fe5d..a1e13a6e7 100644
--- a/src/smt/params/theory_pb_params.cpp
+++ b/src/smt/params/theory_pb_params.cpp
@@ -26,3 +26,12 @@ void theory_pb_params::updt_params(params_ref const & _p) {
     m_pb_enable_compilation = p.pb_enable_compilation();
     m_pb_enable_simplex = p.pb_enable_simplex();
 }
+
+#define DISPLAY_PARAM(X) out << #X"=" << X << std::endl;
+
+void theory_pb_params::display(std::ostream & out) const {
+    DISPLAY_PARAM(m_pb_conflict_frequency);
+    DISPLAY_PARAM(m_pb_learn_complements);
+    DISPLAY_PARAM(m_pb_enable_compilation);
+    DISPLAY_PARAM(m_pb_enable_simplex);
+}
\ No newline at end of file
diff --git a/src/smt/params/theory_pb_params.h b/src/smt/params/theory_pb_params.h
index 2af4f04b7..6a129e601 100644
--- a/src/smt/params/theory_pb_params.h
+++ b/src/smt/params/theory_pb_params.h
@@ -35,6 +35,8 @@ struct theory_pb_params {
     {}
     
     void updt_params(params_ref const & p);
+
+    void display(std::ostream & out) const;
 };
 
 #endif /* THEORY_PB_PARAMS_H_ */
diff --git a/src/smt/smt_solver.cpp b/src/smt/smt_solver.cpp
index d7764ac64..6ae7f107c 100644
--- a/src/smt/smt_solver.cpp
+++ b/src/smt/smt_solver.cpp
@@ -109,10 +109,7 @@ namespace smt {
             }
             scoped_minimize_core scm(*this);
             mus mus(*this);
-            
-            for (unsigned i = 0; i < r.size(); ++i) {
-                VERIFY(i == mus.add_soft(r[i]));
-            }        
+            mus.add_soft(r.size(), r.c_ptr());
             ptr_vector<expr> r2;
             if (l_true == mus.get_mus(r2)) {
                 r.reset();
diff --git a/src/solver/mus.cpp b/src/solver/mus.cpp
index 5f856cd80..a5013cd5a 100644
--- a/src/solver/mus.cpp
+++ b/src/solver/mus.cpp
@@ -22,7 +22,7 @@ Notes:
 #include "mus.h"
 #include "ast_pp.h"
 #include "ast_util.h"
-#include "uint_set.h"
+#include "model_evaluator.h"
 
 
 struct mus::imp {
@@ -59,7 +59,7 @@ struct mus::imp {
         unsigned idx = m_lit2expr.size();
         m_expr2lit.insert(lit, idx);
         m_lit2expr.push_back(lit);
-        TRACE("opt", tout << idx << ": " << mk_pp(lit, m) << "\n" << m_lit2expr << "\n";);
+        TRACE("mus", tout << idx << ": " << mk_pp(lit, m) << "\n" << m_lit2expr << "\n";);
         return idx;
     }
 
@@ -68,42 +68,30 @@ struct mus::imp {
         m_assumptions.push_back(lit);
     }
 
-    lbool get_mus(ptr_vector<expr>& mus) {
-        unsigned_vector result;
-        lbool r = get_mus(result);
-        ids2exprs(mus, result);
-        return r;
-    }
-    
-    lbool get_mus(unsigned_vector& mus_ids) {
-        // SASSERT: mus_ids does not have duplicates.
+    lbool get_mus(expr_ref_vector& mus) {
         m_model.reset();
-        mus_ids.reset();
-        
+        mus.reset();
         if (m_lit2expr.size() == 1) {
-            mus_ids.push_back(0);
+            mus.push_back(m_lit2expr.back());
             return l_true;
         }
-                
-        return get_mus1(mus_ids);
-    }
-
-    lbool get_mus1(unsigned_vector& mus_ids) {
-        expr_ref_vector mus(m);
-        lbool result = get_mus1(mus);
-        for (unsigned i = 0; i < mus.size(); ++i) {
-            mus_ids.push_back(m_expr2lit.find(mus[i].get()));
-        }
-        return result;
+        return get_mus1(mus);
     }
 
+    lbool get_mus(ptr_vector<expr>& mus) {
+        mus.reset();
+        expr_ref_vector result(m);
+        lbool r = get_mus(result);
+        mus.append(result.size(), result.c_ptr());
+        return r;
+    }    
 
     lbool get_mus1(expr_ref_vector& mus) {
         ptr_vector<expr> unknown(m_lit2expr.size(), m_lit2expr.c_ptr());
         ptr_vector<expr> core_exprs;
         while (!unknown.empty()) { 
-            IF_VERBOSE(12, verbose_stream() << "(opt.mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
-            TRACE("opt", display_vec(tout << "core:  ", unknown); display_vec(tout << "mus:   ", mus););
+            IF_VERBOSE(12, verbose_stream() << "(mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
+            TRACE("mus", display_vec(tout << "core:  ", unknown); display_vec(tout << "mus:   ", mus););
             expr* lit = unknown.back();
             unknown.pop_back();
             expr_ref not_lit(mk_not(m, lit), m);
@@ -132,7 +120,7 @@ struct mus::imp {
                             unknown.push_back(core_exprs[i]);
                         }
                     }
-                    TRACE("opt", display_vec(tout << "core exprs:", core_exprs);
+                    TRACE("mus", display_vec(tout << "core exprs:", core_exprs);
                         display_vec(tout << "core:", unknown);
                         display_vec(tout << "mus:", mus);
                     );
@@ -147,42 +135,51 @@ struct mus::imp {
 
     // use correction sets
     lbool get_mus2(expr_ref_vector& mus) {
-        scoped_append _sa1(*this, mus, m_assumptions);
+        expr* lit = 0;
+        lbool is_sat;
         ptr_vector<expr> unknown(m_lit2expr.size(), m_lit2expr.c_ptr());
         while (!unknown.empty()) { 
-            expr* lit;
-            lbool is_sat = get_next_mcs(mus, unknown, lit);
-            switch (is_sat) {
-            case l_undef:
-                return is_sat;
-            case l_false:
+            IF_VERBOSE(12, verbose_stream() << "(mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
+            {
+                scoped_append _sa1(*this, mus, m_assumptions);
+                is_sat = get_next_mcs(mus, unknown, lit);
+            }
+            if (l_false == is_sat) {
                 mus.push_back(lit);
-                break;
-            case l_true:
-                break;
+            }
+            else {
+                return is_sat;
             }
         }        
+        
+        //SASSERT(is_core(mus));
         return l_true;
     }
 
     // find the next literal to be a member of a core.
     lbool get_next_mcs(expr_ref_vector& mus, ptr_vector<expr>& unknown, expr*& core_literal) {
-        ptr_vector<expr> mss, core, min_core;
+        ptr_vector<expr> mss;
+        expr_ref_vector  nmcs(m);
+        expr_set core, min_core, nmcs_set;
         bool min_core_valid = false;
         expr* min_lit = 0;
         while (!unknown.empty()) {
             expr* lit = unknown.back();
             unknown.pop_back();
             model_ref mdl;
-            scoped_append assume_mss(*this, mus, mss);
-            scoped_append assume_lit(*this, mus, lit);
+            scoped_append assume_mss(*this,  mus, mss);      // current satisfied literals
+            scoped_append assume_nmcs(*this, mus, nmcs);     // current non-satisfied literals
+            scoped_append assume_lit(*this,  mus, lit);      // current unknown literal
             switch (m_solver.check_sat(mus)) {
-            case l_true:
+            case l_true: {
+                TRACE("mus", tout << "literal can be satisfied: " << mk_pp(lit, m) << "\n";);
                 mss.push_back(lit);
                 m_solver.get_model(mdl);
+                model_evaluator eval(*mdl.get());
                 for (unsigned i = 0; i < unknown.size(); ) {
                     expr_ref tmp(m);
-                    if (mdl->eval(unknown[i], tmp) && m.is_true(tmp)) {
+                    eval(unknown[i], tmp);
+                    if (m.is_true(tmp)) {
                         mss.push_back(unknown[i]);
                         unknown[i] = unknown.back();
                         unknown.pop_back();
@@ -192,16 +189,27 @@ struct mus::imp {
                     }
                 }
                 break;
+            }
             case l_false:
-                core.reset();
-                m_solver.get_unsat_core(core);
-                // ???
+                TRACE("mus", tout << "literal is in a core: " << mk_pp(lit, m) << "\n";);
+                nmcs.push_back(mk_not(m, lit));
+                nmcs_set.insert(nmcs.back());
+                get_core(core);
                 if (!core.contains(lit)) {
-                    return l_false;
+                    // The current mus is already a core.
+                    unknown.reset();
+                    return l_true;
+                }
+                if (have_intersection(nmcs_set, core)) {
+                    // can't use this core directly. Hypothetically, we 
+                    // could try to combine min_core with core and
+                    // see if the combination produces a better minimal core.
+                    SASSERT(min_core_valid);
+                    break;
                 }
                 if (!min_core_valid || core.size() < min_core.size()) {
-                    min_core.reset();
-                    min_core.append(core);
+                    // The current core is smallest so far, so we get fewer unknowns from it.
+                    min_core = core;
                     min_core_valid = true;
                     min_lit = lit;
                 }
@@ -210,66 +218,57 @@ struct mus::imp {
                 return l_undef;
             }
         }
+        SASSERT(min_core_valid);
         if (!min_core_valid) {
-            // ???
-            UNREACHABLE();
+            // all unknown soft constraints were satisfiable
             return l_true;
         }
-        else {
-            for (unsigned i = 0; i < min_core.size(); ++i) {
-                if (mss.contains(min_core[i]) && min_lit != min_core[i]) {
-                    unknown.push_back(min_core[i]);
-                }
-            }
-            core_literal = min_lit;
+
+        expr_set mss_set;
+        for (unsigned i = 0; i < mss.size(); ++i) {
+            mss_set.insert(mss[i]);
         }
+        expr_set::iterator it = min_core.begin(), end = min_core.end();
+        for (; it != end; ++it) {
+            if (mss_set.contains(*it) && min_lit != *it) {
+                unknown.push_back(*it);
+            }
+        }
+        core_literal = min_lit;
+        
         return l_false;
     }
 
-    expr* lit2expr(unsigned lit_id) const {
-        return m_lit2expr[lit_id];
-    }
-
-    void ids2exprs(ptr_vector<expr>& dst, unsigned_vector const& ids) const {
-        for (unsigned i = 0; i < ids.size(); ++i) {
-            dst.push_back(lit2expr(ids[i]));
-        }        
-    }
-
-    bool is_core(unsigned_vector const& mus_ids) {
-        ptr_vector<expr> mus_exprs;
-        ids2exprs(mus_exprs, mus_ids);
-        return l_false == m_solver.check_sat(mus_exprs.size(), mus_exprs.c_ptr());
-    }
-
-    // dst := A \ B
-    void set_difference(unsigned_vector& dst, ptr_vector<expr> const& A, unsigned_vector const& B) {
-        dst.reset();
-        for (unsigned i = 0; i < A.size(); ++i) {
-            unsigned lit_id;
-            if (m_expr2lit.find(A[i], lit_id) && !B.contains(lit_id)) {
-                dst.push_back(lit_id);
+    bool have_intersection(expr_set const& A, expr_set const& B) {
+        if (A.size() < B.size()) {
+            expr_set::iterator it = A.begin(), end = A.end();
+            for (; it != end; ++it) {
+                if (B.contains(*it)) return true;
             }
         }
+        else {
+            expr_set::iterator it = B.begin(), end = B.end();
+            for (; it != end; ++it) {
+                if (A.contains(*it)) return true;
+            }
+        }
+        return false;
+    }
+
+    bool is_core(expr_ref_vector const& mus) {
+        return l_false == m_solver.check_sat(mus); 
     }
 
     class scoped_append {
         expr_ref_vector& m_fmls;
         unsigned         m_size;
     public:
-        scoped_append(imp& imp, expr_ref_vector& fmls1, unsigned_vector const& fmls2):
+        scoped_append(imp& imp, expr_ref_vector& fmls1, expr_set const& fmls2):
             m_fmls(fmls1),
             m_size(fmls1.size()) {
-            for (unsigned i = 0; i < fmls2.size(); ++i) {
-                fmls1.push_back(imp.lit2expr(fmls2[i]));
-            }            
-        }
-        scoped_append(imp& imp, expr_ref_vector& fmls1, uint_set const& fmls2):
-            m_fmls(fmls1),
-            m_size(fmls1.size()) {
-            uint_set::iterator it = fmls2.begin(), end = fmls2.end();
+            expr_set::iterator it = fmls2.begin(), end = fmls2.end();
             for (; it != end; ++it) {
-                fmls1.push_back(imp.lit2expr(*it));
+                fmls1.push_back(*it);
             }            
         }
         scoped_append(imp& imp, expr_ref_vector& fmls1, expr_ref_vector const& fmls2):
@@ -292,12 +291,6 @@ struct mus::imp {
         }
     };
 
-    void add_core(unsigned_vector const& core, expr_ref_vector& assumptions) {
-        for (unsigned i = 0; i < core.size(); ++i) {
-            assumptions.push_back(lit2expr(core[i]));
-        }
-    }
-
     template<class T>
     void display_vec(std::ostream& out, T const& v) const {
         for (unsigned i = 0; i < v.size(); ++i) {
@@ -353,14 +346,14 @@ struct mus::imp {
     }
 
 
-    lbool qx(unsigned_vector& mus) {
-        uint_set core, support;
+    lbool qx(expr_ref_vector& mus) {
+        expr_set core, support;
         for (unsigned i = 0; i < m_lit2expr.size(); ++i) {
-            core.insert(i);
+            core.insert(m_lit2expr[i].get());
         }
         lbool is_sat = qx(core, support, false);
         if (is_sat == l_true) {
-            uint_set::iterator it = core.begin(), end = core.end();
+            expr_set::iterator it = core.begin(), end = core.end();
             mus.reset();
             for (; it != end; ++it) {
                 mus.push_back(*it);
@@ -369,7 +362,7 @@ struct mus::imp {
         return is_sat;
     }
 
-    lbool qx(uint_set& assignment, uint_set& support, bool has_support) {
+    lbool qx(expr_set& assignment, expr_set& support, bool has_support) {
         lbool is_sat = l_true;
 #if 0
         if (s.m_config.m_minimize_core_partial && s.m_stats.m_restart - m_restart > m_max_restarts) {
@@ -384,7 +377,7 @@ struct mus::imp {
             is_sat = m_solver.check_sat(asms);
             switch (is_sat) {
             case l_false: {
-                uint_set core; 
+                expr_set core; 
                 get_core(core);
                 support &= core;
                 assignment.reset();
@@ -399,10 +392,10 @@ struct mus::imp {
                 break;
             }
         }
-        if (assignment.num_elems() == 1) {
+        if (assignment.size() == 1) {
             return l_true;
         }
-        uint_set assign2;
+        expr_set assign2;
         split(assignment, assign2);
         support |= assignment;
         is_sat = qx(assign2, support, !assignment.empty());        
@@ -415,20 +408,20 @@ struct mus::imp {
         return is_sat;
     }
 
-    void get_core(uint_set& core) {
+    void get_core(expr_set& core) {
+        core.reset();
         ptr_vector<expr> core_exprs;
-        unsigned lit_id;
         m_solver.get_unsat_core(core_exprs);
         for (unsigned i = 0; i < core_exprs.size(); ++i) {
-            if (m_expr2lit.find(core_exprs[i], lit_id)) {
-                core.insert(lit_id);
+            if (m_expr2lit.contains(core_exprs[i])) {
+                core.insert(core_exprs[i]);
             }
         }
     }
 
-    void unsplit(uint_set& A, uint_set& B) {
-        uint_set A1, B1;
-        uint_set::iterator it = A.begin(), end = A.end();
+    void unsplit(expr_set& A, expr_set& B) {
+        expr_set A1, B1;
+        expr_set::iterator it = A.begin(), end = A.end();
         for (; it != end; ++it) {
             if (B.contains(*it)) {
                 B1.insert(*it);
@@ -441,10 +434,10 @@ struct mus::imp {
         B = B1;
     }
 
-    void split(uint_set& lits1, uint_set& lits2) {
-        unsigned half = lits1.num_elems()/2;
-        uint_set lits3;
-        uint_set::iterator it = lits1.begin(), end = lits1.end();
+    void split(expr_set& lits1, expr_set& lits2) {
+        unsigned half = lits1.size()/2;
+        expr_set lits3;
+        expr_set::iterator it = lits1.begin(), end = lits1.end();
         for (unsigned i = 0; it != end; ++it, ++i) {
             if (i < half) {
                 lits3.insert(*it);
@@ -474,7 +467,11 @@ void mus::add_assumption(expr* lit) {
     return m_imp->add_assumption(lit);
 }
 
-lbool mus::get_mus(unsigned_vector& mus) {
+lbool mus::get_mus(ptr_vector<expr>& mus) {
+    return m_imp->get_mus(mus);
+}
+
+lbool mus::get_mus(expr_ref_vector& mus) {
     return m_imp->get_mus(mus);
 }
 
diff --git a/src/solver/mus.h b/src/solver/mus.h
index bb3c6508f..f2e543f04 100644
--- a/src/solver/mus.h
+++ b/src/solver/mus.h
@@ -33,6 +33,10 @@ class mus {
        Assume also that cls is a literal.           
     */
     unsigned add_soft(expr* cls);
+
+    void add_soft(unsigned sz, expr* const* clss) {
+        for (unsigned i = 0; i < sz; ++i) add_soft(clss[i]);
+    }
     
     /**
        Additional assumption for solver to be used along with solver context, 
@@ -43,8 +47,6 @@ class mus {
      */
     void add_assumption(expr* lit);
 
-    lbool get_mus(unsigned_vector& mus);
-
     lbool get_mus(ptr_vector<expr>& mus);
 
     lbool get_mus(expr_ref_vector& mus);
diff --git a/src/util/hashtable.h b/src/util/hashtable.h
index 488157c00..fe51963e0 100644
--- a/src/util/hashtable.h
+++ b/src/util/hashtable.h
@@ -556,6 +556,38 @@ public:
         out << "]";
     }
 
+    core_hashtable& operator|=(core_hashtable const& other) {
+        if (this == &other) return *this;
+        iterator i = begin(), e = end();
+        for (; i != e; ++i) {
+            insert(*i);
+        }
+        return *this;
+    }
+
+
+    core_hashtable& operator&=(core_hashtable const& other) {
+        if (this == &other) return *this;
+        core_hashtable copy(*this);
+        iterator i = copy.begin(), e = copy.end();
+        for (; i != e; ++i) {
+            if (!other.contains(*i)) {
+                remove(*i);
+            }
+        }
+        return *this;
+    }
+
+    core_hashtable& operator=(core_hashtable const& other) {
+        if (this == &other) return *this;
+        reset();
+        core_hashtable::iterator i = other.begin(), e = other.end();
+        for (; i != e; ++i) {
+            insert(*i);
+        }
+        return *this;
+    }
+
 #ifdef Z3DEBUG
     bool check_invariant() {
         entry * curr = m_table;
@@ -582,9 +614,6 @@ public:
     unsigned long long get_num_collision() const { return 0; }
 #endif
 
- private:
-
-    core_hashtable& operator=(core_hashtable const&);
     
 };
 
@@ -640,4 +669,5 @@ public:
         core_hashtable<int_hash_entry<INT_MIN, INT_MIN + 1>, HashProc, EqProc>(initial_capacity, h, e) {}
 };
 
+
 #endif /* HASHTABLE_H_ */
diff --git a/src/util/obj_hashtable.h b/src/util/obj_hashtable.h
index 4e948d96d..383ecaeb3 100644
--- a/src/util/obj_hashtable.h
+++ b/src/util/obj_hashtable.h
@@ -51,6 +51,7 @@ class obj_hashtable : public core_hashtable<obj_hash_entry<T>, obj_ptr_hash<T>,
 public:
     obj_hashtable(unsigned initial_capacity = DEFAULT_HASHTABLE_INITIAL_CAPACITY):
         core_hashtable<obj_hash_entry<T>, obj_ptr_hash<T>, ptr_eq<T> >(initial_capacity) {}
+
 };
 
 template<typename Key, typename Value>