Make IPAddress final

mq/main/comm-util/src/main/java/com/sun/messaging/jmq/util/net/IPAddress.java

@@ -47,7 +47,7 @@
  * The leading 11111111 is used in IPv6 to signify an IPv6 multicast address. Since a client will never be assigned a
  * multicast address we can use this prefix to indicate an IPv4+MAC address.
  */
-public class IPAddress implements Cloneable, Serializable {
+public final class IPAddress implements Cloneable, Serializable {
 
     private static final long serialVersionUID = -3749627756354392982L;