--- old/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serialize/BaseMarkupSerializer.java	2017-11-06 22:19:30.326317021 -0800
+++ new/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serialize/BaseMarkupSerializer.java	2017-11-06 22:19:29.873272833 -0800
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
- * @LastModified: Oct 2017
+ * @LastModified: Nov 2017
  */
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
@@ -1902,7 +1902,7 @@
         }
         for ( int i = _elementStateCount ; i > 0 ; --i ) {
             if ( _elementStates[ i ].prefixes != null ) {
-                prefix = (String) _elementStates[ i ].prefixes.get( namespaceURI );
+                prefix = _elementStates[ i ].prefixes.get( namespaceURI );
                 if ( prefix != null )
                     return prefix;
             }