diff --git a/src/java/org/apache/lucene/index/IndexWriter.java b/src/java/org/apache/lucene/index/IndexWriter.java
index 074a2d17c79..45b956fe586 100644
--- a/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/src/java/org/apache/lucene/index/IndexWriter.java
@@ -468,8 +468,7 @@ public class IndexWriter implements Closeable {
         // not pooling readers, we release it:
         readerMap.remove(sr.getSegmentInfo());
 
-        // TODO: java 5
-        // assert !sr.hasChanges || Thread.holdsLock(IndexWriter.this);
+        assert !sr.hasChanges || Thread.holdsLock(IndexWriter.this);
 
         // Drop our ref -- this will commit any pending
         // changes to the dir