HADOOP-12282. Connection thread's name should be updated after address changing is detected. Contributed by Lisheng Sun.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Client.java

@@ -638,6 +638,10 @@ private synchronized boolean updateAddress() throws IOException {
         LOG.warn("Address change detected. Old: " + server.toString() +
                                  " New: " + currentAddr.toString());
         server = currentAddr;
+        UserGroupInformation ticket = remoteId.getTicket();
+        this.setName("IPC Client (" + socketFactory.hashCode()
+            + ") connection to " + server.toString() + " from "
+            + ((ticket == null) ? "an unknown user" : ticket.getUserName()));
         return true;
       }
       return false;