Index: modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemmer.java
===================================================================
--- modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemmer.java	(revision 1134289)
+++ modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemmer.java	(working copy)
@@ -1373,6 +1373,10 @@
     return word.toString();
   }
   
+  CharSequence asCharSequence() {
+    return result != null ? result : word;
+  }
+  
   String getString() {
     return result;
   }
Index: modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemFilter.java
===================================================================
--- modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemFilter.java	(revision 1134289)
+++ modules/analysis/common/src/java/org/apache/lucene/analysis/en/KStemFilter.java	(working copy)
@@ -55,8 +55,7 @@
     char[] term = termAttribute.buffer();
     int len = termAttribute.length();
     if ((!keywordAtt.isKeyword()) && stemmer.stem(term, len)) {
-      char[] chars = stemmer.asString().toCharArray();
-      termAttribute.copyBuffer(chars, 0, chars.length);
+      termAttribute.setEmpty().append(stemmer.asCharSequence());
     }
 
     return true;