diff -r 1f7f707c1aa9 -r 54ffb15c4839 src/java.management.rmi/share/classes/com/sun/jmx/remote/internal/rmi/ProxyRef.java
--- a/src/java.management.rmi/share/classes/com/sun/jmx/remote/internal/rmi/ProxyRef.java	Wed Oct 23 18:34:25 2019 +0200
+++ b/src/java.management.rmi/share/classes/com/sun/jmx/remote/internal/rmi/ProxyRef.java	Wed Oct 23 13:01:40 2019 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2019, 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
@@ -35,7 +35,8 @@
 import java.rmi.server.RemoteRef;
 
 
-@SuppressWarnings("deprecation")
+@SuppressWarnings({"deprecation",
+                   "serial"}) // Externalizable class w/o no-arg c'tor
 public class ProxyRef implements RemoteRef {
     private static final long serialVersionUID = -6503061366316814723L;