ZOOKEEPER-4877: Fix typos in comments

Reviewers: kezhuw, shoothzj
Author: luozongle01
Closes #2203 from luozongle01/ZOOKEEPER-4877

zookeeper-recipes/zookeeper-recipes-election/src/main/java/org/apache/zookeeper/recipes/leader/LeaderElectionSupport.java

@@ -278,7 +278,7 @@ public class LeaderElectionSupport implements Watcher {
      * Fetch the (user supplied) hostname of the current leader. Note that by the
      * time this method returns, state could have changed so do not depend on this
      * to be strongly consistent. This method has to read all leader offers from
-     * ZooKeeper to deterime who the leader is (i.e. there is no caching) so
+     * ZooKeeper to determine who the leader is (i.e. there is no caching) so
      * consider the performance implications of frequent invocation. If there are
      * no leader offers this method returns null.
      *

zookeeper-server/src/main/java/org/apache/zookeeper/ClientCnxnSocketNetty.java

@@ -402,7 +402,7 @@ public class ClientCnxnSocketNetty extends ClientCnxnSocket {
         }
     }
 
-    // *************** <END> CientCnxnSocketNetty </END> ******************
+    // *************** <END> ClientCnxnSocketNetty </END> ******************
     private static class WakeupPacket {
 
         private static final Packet instance = new Packet(null, null, null, null, null);

zookeeper-server/src/main/java/org/apache/zookeeper/metrics/MetricsProviderLifeCycleException.java

@@ -19,7 +19,7 @@
 package org.apache.zookeeper.metrics;
 
 /**
- * A generic exception thrown during the licecycle of a MetricsProvider.
+ * A generic exception thrown during the lifecycle of a MetricsProvider.
  * <p>These exception will prevent the system from booting.</p>
  * <p>Normally these exception will be ignored during shutdown.</p>
  */

zookeeper-server/src/main/java/org/apache/zookeeper/server/DatadirCleanupManager.java

@@ -66,8 +66,8 @@ public class DatadirCleanupManager {
      *            transaction log directory
      * @param snapRetainCount
      *            number of snapshots to be retained after purge
-     * @param purgeInterval
-     *            purge interval in hours
+     * @param purgeIntervalInMs
+     *            purge interval in milliseconds
      */
     public DatadirCleanupManager(File snapDir, File dataLogDir, int snapRetainCount, int purgeIntervalInMs) {
         this.snapDir = snapDir;

zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Leader.java

@@ -410,7 +410,7 @@ public class Leader extends LearnerMaster {
 
     /**
      * This message type is sent by the leader to indicate that the follower is
-     * now uptodate andt can start responding to clients.
+     * now uptodate and can start responding to clients.
      */
     static final int UPTODATE = 12;