diff --git a/src/test/java/org/apache/log4j/helpers/VersionUtilTest.java b/src/test/java/org/apache/log4j/helpers/VersionUtilTest.java
index fc53dd73..27662813 100644
--- a/src/test/java/org/apache/log4j/helpers/VersionUtilTest.java
+++ b/src/test/java/org/apache/log4j/helpers/VersionUtilTest.java
@@ -18,6 +18,6 @@ public void smoke() {
         assertEquals(9, VersionUtil.getJavaMajorVersion("9.0.1"));
         assertEquals(18, VersionUtil.getJavaMajorVersion("18.3+xx"));
         assertEquals(19, VersionUtil.getJavaMajorVersion("19"));
-
+        assertEquals(21, VersionUtil.getJavaMajorVersion("21"));
    }
 }