--- old/src/java.base/share/classes/java/lang/reflect/Proxy.java	Tue Mar  8 21:59:11 2016
+++ new/src/java.base/share/classes/java/lang/reflect/Proxy.java	Tue Mar  8 21:59:10 2016
@@ -708,7 +708,7 @@
                 throw new InternalError("Proxy is not supported until module system is fully initialzed");
             }
             if (interfaces.size() > 65535) {
-                throw new IllegalArgumentException("interface limit exceeded");
+                throw new IllegalArgumentException("interface limit exceeded: " + interfaces.size());
             }
 
             Set<Class<?>> refTypes = referencedTypes(loader, interfaces);