--- old/src/share/vm/services/mallocTracker.hpp	2014-08-12 07:52:22.079968000 -0700
+++ new/src/share/vm/services/mallocTracker.hpp	2014-08-12 07:52:21.028065000 -0700
@@ -171,8 +171,9 @@
   // Total malloc'd memory used by arenas
   size_t total_arena() const;
 
-  inline size_t thread_count() {
-    return by_type(mtThreadStack)->malloc_count();
+  inline size_t thread_count() const {
+    MallocMemorySnapshot* s = const_cast<MallocMemorySnapshot*>(this); 
+    return s->by_type(mtThreadStack)->malloc_count();
   }
 
   void reset();