HBASE-19761:Fix Checkstyle errors in hbase-zookeeper

Author: maoling

hbase-zookeeper/pom.xml

@@ -91,6 +91,22 @@
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>findbugs-maven-plugin</artifactId>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>checkstyle</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+            <configuration>
+              <failOnViolation>true</failOnViolation>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>net.revelc.code</groupId>
         <artifactId>warbucks-maven-plugin</artifactId>

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/MetaTableLocator.java

@@ -388,7 +388,7 @@ private static AdminService.BlockingInterface getCachedConnection(ClusterConnect
       service = connection.getAdmin(sn);
     } catch (RetriesExhaustedException e) {
       if (e.getCause() != null && e.getCause() instanceof ConnectException) {
-        // Catch this; presume it means the cached connection has gone bad.
+        LOG.debug("Catch this; presume it means the cached connection has gone bad.");
       } else {
         throw e;
       }
@@ -407,12 +407,12 @@ private static AdminService.BlockingInterface getCachedConnection(ClusterConnect
     } catch (IOException ioe) {
       Throwable cause = ioe.getCause();
       if (ioe instanceof ConnectException) {
-        // Catch. Connect refused.
+        LOG.debug("Catch. Connect refused.");
       } else if (cause != null && cause instanceof EOFException) {
-        // Catch. Other end disconnected us.
+        LOG.debug("Catch. Other end disconnected us.");
       } else if (cause != null && cause.getMessage() != null &&
         cause.getMessage().toLowerCase(Locale.ROOT).contains("connection reset")) {
-        // Catch. Connection reset.
+        LOG.debug("Catch. Connection reset.");
       } else {
         throw ioe;
       }

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKMainServer.java

@@ -57,9 +57,9 @@ public HACK_UNTIL_ZOOKEEPER_1897_ZooKeeperMain(String[] args)
 
     /**
      * Run the command-line args passed.  Calls System.exit when done.
-     * @throws KeeperException
-     * @throws IOException
-     * @throws InterruptedException
+     * @throws KeeperException zookeeper exception
+     * @throws IOException if fail to runCmdLine
+     * @throws InterruptedException unexpected thread exception
      */
     void runCmdLine() throws KeeperException, IOException, InterruptedException {
       processCmd(this.cl);

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKWatcher.java

@@ -76,14 +76,14 @@ public class ZKWatcher implements Watcher, Abortable, Closeable {
   // Used if abortable is null
   private boolean aborted = false;
 
-  public final ZNodePaths znodePaths;
+  protected final ZNodePaths znodePaths;
 
   // listeners to be notified
   private final List<ZKListener> listeners = new CopyOnWriteArrayList<>();
 
   // Used by ZKUtil:waitForZKConnectionIfAuthenticating to wait for SASL
   // negotiation to complete
-  public CountDownLatch saslLatch = new CountDownLatch(1);
+  private CountDownLatch saslLatch = new CountDownLatch(1);
 
   private final Configuration conf;
 
@@ -95,7 +95,7 @@ public class ZKWatcher implements Watcher, Abortable, Closeable {
    * @param identifier string that is passed to RecoverableZookeeper to be used as
    *                   identifier for this instance. Use null for default.
    * @throws IOException if the connection to ZooKeeper fails
-   * @throws ZooKeeperConnectionException
+   * @throws ZooKeeperConnectionException if the client can't connect to zookeeper
    */
   public ZKWatcher(Configuration conf, String identifier,
                    Abortable abortable) throws ZooKeeperConnectionException, IOException {
@@ -111,7 +111,7 @@ public ZKWatcher(Configuration conf, String identifier,
    *          context.
    * @param canCreateBaseZNode true if a base ZNode can be created
    * @throws IOException if the connection to ZooKeeper fails
-   * @throws ZooKeeperConnectionException
+   * @throws ZooKeeperConnectionException if the client can't connect to zookeeper
    */
   public ZKWatcher(Configuration conf, String identifier,
                    Abortable abortable, boolean canCreateBaseZNode)
@@ -517,6 +517,8 @@ public void process(WatchedEvent event) {
         }
         break;
       }
+      default:
+        throw new IllegalStateException("Received event is not valid: " + event.getState());
     }
   }
 

hbase-zookeeper/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZKLeaderManager.java

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.zookeeper;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;

hbase-zookeeper/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZKMainServer.java

@@ -43,7 +43,7 @@ public class TestZKMainServer {
   // http://stackoverflow.com/questions/309396/java-how-to-test-methods-that-call-system-exit
   protected static class ExitException extends SecurityException {
     private static final long serialVersionUID = 1L;
-    public final int status;
+    private final int status;
     public ExitException(int status) {
       super("There is no escape!");
       this.status = status;