diff --git a/dubbo-common/src/main/java/org/apache/dubbo/common/URL.java b/dubbo-common/src/main/java/org/apache/dubbo/common/URL.java
index 6e71e749d8c..31ac91e5716 100644
--- a/dubbo-common/src/main/java/org/apache/dubbo/common/URL.java
+++ b/dubbo-common/src/main/java/org/apache/dubbo/common/URL.java
@@ -436,9 +436,8 @@ public List<URL> getBackupUrls() {
         return urls;
     }
 
-    private String appendDefaultPort(String address, int defaultPort) {
-        if (address != null && address.length() > 0
-                && defaultPort > 0) {
+    static String appendDefaultPort(String address, int defaultPort) {
+        if (address != null && address.length() > 0 && defaultPort > 0) {
             int i = address.indexOf(':');
             if (i < 0) {
                 return address + ":" + defaultPort;
diff --git a/dubbo-common/src/test/java/org/apache/dubbo/common/URLTest.java b/dubbo-common/src/test/java/org/apache/dubbo/common/URLTest.java
index b4f547ce12b..8061ab2e270 100644
--- a/dubbo-common/src/test/java/org/apache/dubbo/common/URLTest.java
+++ b/dubbo-common/src/test/java/org/apache/dubbo/common/URLTest.java
@@ -18,6 +18,7 @@
 
 import org.apache.dubbo.common.utils.CollectionUtils;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import java.io.File;
@@ -124,7 +125,7 @@ public void test_valueOf_noHost() throws Exception {
         assertEquals("home/user1/router.js", url.getPath());
         assertEquals(0, url.getParameters().size());
 
-        // Caution!! 
+        // Caution!!
         url = URL.valueOf("file://home/user1/router.js");
         //                      ^^ only tow slash!
         assertEquals("file", url.getProtocol());
@@ -680,4 +681,10 @@ public void testIpV6AddressWithScopeId(){
         assertEquals("1.0.0", url.getParameter("version"));
         assertEquals("morgan", url.getParameter("application"));
     }
-}
\ No newline at end of file
+
+    @Test
+    public void testDefaultPort() {
+        Assertions.assertEquals("10.20.153.10:2181", URL.appendDefaultPort("10.20.153.10:0", 2181));
+        Assertions.assertEquals("10.20.153.10:2181", URL.appendDefaultPort("10.20.153.10", 2181));
+    }
+}
diff --git a/dubbo-registry/dubbo-registry-zookeeper/src/main/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistry.java b/dubbo-registry/dubbo-registry-zookeeper/src/main/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistry.java
index 3ead544a64f..14c3304b622 100644
--- a/dubbo-registry/dubbo-registry-zookeeper/src/main/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistry.java
+++ b/dubbo-registry/dubbo-registry-zookeeper/src/main/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistry.java
@@ -79,18 +79,6 @@ public ZookeeperRegistry(URL url, ZookeeperTransporter zookeeperTransporter) {
         });
     }
 
-    static String appendDefaultPort(String address) {
-        if (address != null && address.length() > 0) {
-            int i = address.indexOf(':');
-            if (i < 0) {
-                return address + ":" + DEFAULT_ZOOKEEPER_PORT;
-            } else if (Integer.parseInt(address.substring(i + 1)) == 0) {
-                return address.substring(0, i + 1) + DEFAULT_ZOOKEEPER_PORT;
-            }
-        }
-        return address;
-    }
-
     @Override
     public boolean isAvailable() {
         return zkClient.isConnected();
diff --git a/dubbo-registry/dubbo-registry-zookeeper/src/test/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistryTest.java b/dubbo-registry/dubbo-registry-zookeeper/src/test/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistryTest.java
index 7420d836e26..c2dd23129d6 100644
--- a/dubbo-registry/dubbo-registry-zookeeper/src/test/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistryTest.java
+++ b/dubbo-registry/dubbo-registry-zookeeper/src/test/java/org/apache/dubbo/registry/zookeeper/ZookeeperRegistryTest.java
@@ -36,7 +36,9 @@
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 
-import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.mockito.Mockito.mock;
 
@@ -65,12 +67,6 @@ public void tearDown() throws Exception {
         zkServer.stop();
     }
 
-    @Test
-    public void testDefaultPort() {
-        Assertions.assertEquals("10.20.153.10:2181", ZookeeperRegistry.appendDefaultPort("10.20.153.10:0"));
-        Assertions.assertEquals("10.20.153.10:2181", ZookeeperRegistry.appendDefaultPort("10.20.153.10"));
-    }
-
     @Test
     public void testAnyHost() {
         Assertions.assertThrows(IllegalStateException.class, () -> {
@@ -153,13 +149,8 @@ public void testStatusChecker() {
     public void testSubscribeAnyValue() throws InterruptedException {
         final CountDownLatch latch = new CountDownLatch(1);
         zookeeperRegistry.register(serviceUrl);
-        zookeeperRegistry.subscribe(anyUrl, new NotifyListener() {
-            @Override
-            public void notify(List<URL> urls) {
-                latch.countDown();
-            }
-        });
+        zookeeperRegistry.subscribe(anyUrl, urls -> latch.countDown());
         zookeeperRegistry.register(serviceUrl);
         latch.await();
     }
-}
\ No newline at end of file
+}