diff --git a/modules/grouping/src/java/org/apache/lucene/search/grouping/package.html b/modules/grouping/src/java/org/apache/lucene/search/grouping/package.html
index dea41e41155..173b736ff38 100644
--- a/modules/grouping/src/java/org/apache/lucene/search/grouping/package.html
+++ b/modules/grouping/src/java/org/apache/lucene/search/grouping/package.html
@@ -176,7 +176,7 @@ fields, <code>FieldCache</code>, etc.).
   int[] groupHeadsArray = c.retrieveGroupHeads()
   // Return all group heads as OpenBitSet.
   int maxDoc = s.maxDoc();
-  OpenBitSet groupHeadsBitSet = c.retrieveGroupHeads(maxDoc)
+  FixedBitSet groupHeadsBitSet = c.retrieveGroupHeads(maxDoc)
 </pre>
 
 </body>