public synchronized void setNativeMethodPrefix(ClassFileTransformer transformer, String prefix) {
   if (!isNativeMethodPrefixSupported()) {
     throw new UnsupportedOperationException(
         "setNativeMethodPrefix is not supported in this environment");
   }
   if (transformer == null) {
     throw new NullPointerException("null passed as 'transformer' in setNativeMethodPrefix");
   }
   TransformerManager mgr = findTransformerManager(transformer);
   if (mgr == null) {
     throw new IllegalArgumentException("transformer not registered in setNativeMethodPrefix");
   }
   mgr.setNativeMethodPrefix(transformer, prefix);
   String[] prefixes = mgr.getNativeMethodPrefixes();
   setNativeMethodPrefixes(mNativeAgent, prefixes, mgr.isRetransformable());
 }