Index: subversion/bindings/javahl/native/OperationContext.cpp
===================================================================
--- subversion/bindings/javahl/native/OperationContext.cpp	(revision 1880687)
+++ subversion/bindings/javahl/native/OperationContext.cpp	(working copy)
@@ -629,6 +629,12 @@
           jtunnel_name, juser, jhostname, jint(port)),
       SVN_ERR_BASE);
 
+  if (tc->jclosecb)
+    {
+      tc->jclosecb = env->NewGlobalRef(tc->jclosecb);
+      SVN_JNI_CATCH(, SVN_ERR_BASE);
+    }
+
   return SVN_NO_ERROR;
 }
 
@@ -656,4 +662,5 @@
       SVN_JNI_CATCH_VOID(mid = env->GetMethodID(cls, "closeTunnel", "()V"));
     }
   SVN_JNI_CATCH_VOID(env->CallVoidMethod(jclosecb, mid));
+  env->DeleteGlobalRef(jclosecb);
 }