diff --git a/lucene/luke/src/java/org/apache/lucene/luke/models/commits/CommitsImpl.java b/lucene/luke/src/java/org/apache/lucene/luke/models/commits/CommitsImpl.java
index 23cc68ae70b..f1dcf43547a 100644
--- a/lucene/luke/src/java/org/apache/lucene/luke/models/commits/CommitsImpl.java
+++ b/lucene/luke/src/java/org/apache/lucene/luke/models/commits/CommitsImpl.java
@@ -200,7 +200,7 @@ public final class CommitsImpl extends LukeModel implements Commits {
     if (dir == null) {
       return Collections.emptyMap();
     }
-    return Map.copyOf(commitMap);
+    return new TreeMap<>(commitMap);
   }
 
   private SegmentInfos findSegmentInfos(long commitGen) throws LukeException, IOException {