--- old/src/java.management/share/classes/sun/management/StackTraceElementCompositeData.java	Tue Mar  8 21:59:26 2016
+++ new/src/java.management/share/classes/sun/management/StackTraceElementCompositeData.java	Tue Mar  8 21:59:26 2016
@@ -148,7 +148,7 @@
         if (!isTypeMatched(stackTraceElementCompositeType, ct)) {
             if (!isTypeMatched(stackTraceElementV6CompositeType, ct)) {
                 throw new IllegalArgumentException(
-                    "Unexpected composite type for StackTraceElement");
+                    "Unexpected composite type for StackTraceElement: " + ct);
             }
         }
     }