From ef80645a71e2e46190bf631e7f5a345315b132cb Mon Sep 17 00:00:00 2001
From: "Christoph M. Wintersteiger" <cwinter@microsoft.com>
Date: Wed, 14 Oct 2015 22:13:43 +0100
Subject: [PATCH] Java API context deletion concurrency fix.

Relates to #205 #245
---
 src/api/java/Context.java | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/api/java/Context.java b/src/api/java/Context.java
index 56f9e008c..1bc01857b 100644
--- a/src/api/java/Context.java
+++ b/src/api/java/Context.java
@@ -3809,14 +3809,16 @@ public class Context extends IDisposable
         m_intSort = null;
         m_realSort = null;
 
-        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.");
+        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;
             }
-            m_ctx = 0;
         }
     }
 }