--- a/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serialize/BaseMarkupSerializer.java	Tue Sep 05 13:40:14 2017 +0200
+++ b/src/java.xml/share/classes/com/sun/org/apache/xml/internal/serialize/BaseMarkupSerializer.java	Wed Oct 18 13:25:49 2017 -0700
@@ -1,5 +1,6 @@
 /*
- * Copyright (c) 2015, 2017 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
+ * @LastModified: Oct 2017
  */
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
@@ -53,9 +54,10 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.Writer;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
-import java.util.Vector;
 import org.w3c.dom.DOMError;
 import org.w3c.dom.DOMErrorHandler;
 import org.w3c.dom.Document;
@@ -161,10 +163,10 @@
 
 
     /**
-     * Vector holding comments and PIs that come before the root
+     * List holding comments and PIs that come before the root
      * element (even after it), see {@link #serializePreRoot}.
      */
-    private Vector          _preRoot;
+    private List<String> _preRoot;
 
 
     /**
@@ -641,8 +643,8 @@
         // the PI directly but place it in the pre-root vector.
         if ( isDocumentState() ) {
             if ( _preRoot == null )
-                _preRoot = new Vector();
-            _preRoot.addElement( fStrBuffer.toString() );
+                _preRoot = new ArrayList<>();
+            _preRoot.add( fStrBuffer.toString() );
         } else {
             _printer.indent();
             printText( fStrBuffer.toString(), true, true );
@@ -688,8 +690,8 @@
         // the comment directly but place it in the pre-root vector.
         if ( isDocumentState() ) {
             if ( _preRoot == null )
-                _preRoot = new Vector();
-            _preRoot.addElement( fStrBuffer.toString() );
+                _preRoot = new ArrayList<>();
+            _preRoot.add( fStrBuffer.toString() );
         } else {
             // Indent this element on a new line if the first
             // content of the parent element or immediately
@@ -1479,11 +1481,11 @@
 
         if ( _preRoot != null ) {
             for ( i = 0 ; i < _preRoot.size() ; ++i ) {
-                printText( (String) _preRoot.elementAt( i ), true, true );
+                printText(_preRoot.get( i ), true, true );
                 if ( _indenting )
                 _printer.breakLine();
             }
-            _preRoot.removeAllElements();
+            _preRoot.clear();
         }
     }