diff -r 6228104986ca -r d825a8a2bd39 src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp	Wed Mar 05 17:37:04 2008 -0800
+++ b/src/share/vm/runtime/globals.hpp	Tue Mar 11 14:19:53 2008 -0700
@@ -586,7 +586,7 @@
   develop(bool, ZapJNIHandleArea, trueInDebug,                              \
           "Zap freed JNI handle space with 0xFEFEFEFE")                     \
                                                                             \
-  develop(bool, ZapUnusedHeapArea, trueInDebug,                             \
+  develop(bool, ZapUnusedHeapArea, false,                                   \
           "Zap unused heap space with 0xBAADBABE")                          \
                                                                             \
   develop(bool, PrintVMMessages, true,                                      \