diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene49/Lucene49NormsConsumer.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene49/Lucene49NormsConsumer.java
index 737e5bc3783..283b054c4a7 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene49/Lucene49NormsConsumer.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene49/Lucene49NormsConsumer.java
@@ -210,8 +210,8 @@ class Lucene49NormsConsumer extends DocValuesConsumer {
   // specialized deduplication of long->ord for norms: 99.99999% of the time this will be a single-byte range.
   static class NormMap {
     // we use short: at most we will add 257 values to this map before its rejected as too big above.
-    short[] singleByteRange = new short[256];
-    Map<Long,Short> other = new HashMap<Long,Short>();
+    final short[] singleByteRange = new short[256];
+    final Map<Long,Short> other = new HashMap<Long,Short>();
     int size;
     
     {