diff --git a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/async/TestDisableNameservicesExample.java b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/async/TestDisableNameservicesExample.java
index b18e7c084a189..54c9cbda634e5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/async/TestDisableNameservicesExample.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/async/TestDisableNameservicesExample.java
@@ -73,12 +73,15 @@
 @SuppressWarnings("checkstyle:VisibilityModifier")
 public class TestDisableNameservicesExample {
 
+  public static final String ASYNC_MODE = "ASYNC";
+  public static final String SYNC_MODE = "SYNC";
+
   @Nested
   @ExtendWith(RouterServerHelper.class)
   class TestWithAsyncRouterRpc {
 
     @ParameterizedTest
-    @ValueSource(strings = {"ASYNC"})
+    @ValueSource(strings = {ASYNC_MODE})
     public void testMetricsAsync(String rpcMode) throws Exception {
       testMetrics();
     }
@@ -101,19 +104,19 @@ public void testWithoutDisablingAsync() throws IOException {
   class TestWithSyncRouterRpc {
 
     @ParameterizedTest
-    @ValueSource(strings = {"SYNC"})
+    @ValueSource(strings = {SYNC_MODE})
     public void testMetricsSync(String rpcMode) throws Exception {
       testMetrics();
     }
 
     @ParameterizedTest
-    @ValueSource(strings = {"SYNC"})
+    @ValueSource(strings = {SYNC_MODE})
     public void testDisablingSync() throws Exception {
       testDisabling();
     }
 
     @ParameterizedTest
-    @ValueSource(strings = {"SYNC"})
+    @ValueSource(strings = {SYNC_MODE})
     public void testWithoutDisablingSync() throws IOException {
       testWithoutDisabling();
     }
@@ -325,9 +328,9 @@ public void beforeEach(ExtensionContext context) throws Exception {
     ValueSource enumAnnotation = testMethod.getAnnotation(ValueSource.class);
     if (enumAnnotation != null) {
       String[] strings = enumAnnotation.strings();
-      for (String s : strings) {
+      for (String rpcMode : strings) {
         if (TEST_ROUTER_SERVER_TL.get() == null) {
-          setUp(s);
+          setUp(rpcMode);
         }
       }
     }