diff --git a/org.jhotdraw8.icollection/src/test/java/org.jhotdraw8.icollection/org/jhotdraw8/icollection/jmh/MutableChampSetJmh.java b/org.jhotdraw8.icollection/src/test/java/org.jhotdraw8.icollection/org/jhotdraw8/icollection/jmh/MutableChampSetJmh.java
index af31f9526..ed9a2c4ac 100644
--- a/org.jhotdraw8.icollection/src/test/java/org.jhotdraw8.icollection/org/jhotdraw8/icollection/jmh/MutableChampSetJmh.java
+++ b/org.jhotdraw8.icollection/src/test/java/org.jhotdraw8.icollection/org/jhotdraw8/icollection/jmh/MutableChampSetJmh.java
@@ -47,7 +47,7 @@ public ChampSet<Integer> mAddMutableOneByOne() {
         for (int i = 0; i < size; i++) {
             set.add(rng.nextInt());
         }
-        return set.toImmutable();
+        return set.toPersistent();
     }
 
     @Benchmark