diff -r bf8edbcae43a -r fe033d997ddf src/share/classes/com/sun/tools/classfile/Instruction.java
--- a/src/share/classes/com/sun/tools/classfile/Instruction.java	Wed Jun 04 20:01:13 2014 +0100
+++ b/src/share/classes/com/sun/tools/classfile/Instruction.java	Tue Dec 17 10:55:59 2013 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,8 @@
 
 package com.sun.tools.classfile;
 
+import java.util.Locale;
+
 /**
  * See JVMS, chapter 6.
  *
@@ -211,7 +213,7 @@
         if (opcode == null)
             return "bytecode " + getUnsignedByte(0);
         else
-            return opcode.toString().toLowerCase();
+            return opcode.toString().toLowerCase(Locale.US);
     }
 
     /** Get the length, in bytes, of this instruction, including the opcode