Fix ut & checkstyle

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/package-info.java

@@ -0,0 +1,25 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The Balancer is a tool for balancing the data across
+ * the storage devices of an HDFS cluster.
+ * Over time, the data in the HDFS storage can become skewed,
+ * The Balancer moves data blocks between DataNodes to balance data distribution.
+ */
+package org.apache.hadoop.hdfs.server.balancer;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancerHttpServer.java

@@ -25,7 +25,6 @@
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
-import org.junit.jupiter.api.Assertions;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileUtil;
@@ -36,6 +35,8 @@
 import org.apache.hadoop.security.ssl.KeyStoreTestUtil;
 import org.apache.hadoop.test.GenericTestUtils;
 
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
 public class TestBalancerHttpServer {
   private static final String BASEDIR =
       GenericTestUtils.getTempPath(TestBalancerHttpServer.class.getSimpleName());
@@ -67,13 +68,16 @@ public static void tearDown() throws Exception {
 
   @Test
   public void testHttpServer() throws Exception {
-    BalancerHttpServer server = new BalancerHttpServer(conf);
+    BalancerHttpServer server = null;
     try {
+      server = new BalancerHttpServer(conf);
       server.start();
-      Assertions.assertTrue(checkConnection("http", server.getHttpAddress()));
-      Assertions.assertTrue(checkConnection("https", server.getHttpsAddress()));
+      assertThat(checkConnection("http", server.getHttpAddress())).isTrue();
+      assertThat(checkConnection("https", server.getHttpsAddress())).isTrue();
     } finally {
-      server.stop();
+      if (server != null) {
+        server.stop();
+      }
     }
   }
 
@@ -84,11 +88,13 @@ private boolean checkConnection(String scheme, InetSocketAddress address) {
     try {
       URL url = new URL(scheme + "://" + NetUtils.getHostPortString(address));
       URLConnection conn = connectionFactory.openConnection(url);
+      conn.setConnectTimeout(5 * 1000);
+      conn.setReadTimeout(5 * 1000);
       conn.connect();
       conn.getContent();
+      return true;
     } catch (Exception e) {
       return false;
     }
-    return true;
   }
 }