--- a/jdk/src/java.base/share/classes/java/io/StringWriter.java	Wed Jul 01 22:17:32 2015 +0300
+++ b/jdk/src/java.base/share/classes/java/io/StringWriter.java	Thu Jul 02 00:26:35 2015 +0300
@@ -109,7 +109,7 @@
      * @param  len  Number of characters to write
      */
     public void write(String str, int off, int len)  {
-        buf.append(str.substring(off, off + len));
+        buf.append(str, off, off + len);
     }
 
     /**