--- a/hotspot/src/share/vm/utilities/debug.cpp	Tue Sep 06 13:01:27 2016 +0200
+++ b/hotspot/src/share/vm/utilities/debug.cpp	Sun Sep 18 21:10:48 2016 -0400
@@ -282,6 +282,12 @@
 }
 
 void report_out_of_shared_space(SharedSpaceType shared_space) {
+  if (shared_space == SharedOptional) {
+    // The estimated shared_optional_space size is large enough
+    // for all class bytes.  It should not run out of space.
+    ShouldNotReachHere();
+  }
+
   static const char* name[] = {
     "shared read only space",
     "shared read write space",