diff --git a/src/api/java/IDecRefQueue.java b/src/api/java/IDecRefQueue.java
index 823288a20..1a99a3d92 100644
--- a/src/api/java/IDecRefQueue.java
+++ b/src/api/java/IDecRefQueue.java
@@ -21,7 +21,7 @@ import java.util.LinkedList;
 
 public abstract class IDecRefQueue
 {
-    protected Object m_lock = new Object();
+    protected final Object m_lock = new Object();
     protected LinkedList<Long> m_queue = new LinkedList<Long>();
     protected int m_move_limit;