You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@falcon.apache.org by sr...@apache.org on 2013/04/26 17:50:42 UTC

[26/47] git commit: Check style fixes relating to common module

Check style fixes relating to common module


Project: http://git-wip-us.apache.org/repos/asf/incubator-falcon/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-falcon/commit/bdadf2ed
Tree: http://git-wip-us.apache.org/repos/asf/incubator-falcon/tree/bdadf2ed
Diff: http://git-wip-us.apache.org/repos/asf/incubator-falcon/diff/bdadf2ed

Branch: refs/heads/master
Commit: bdadf2ed680b338d3ec48cb179300f50db69fee0
Parents: b1fcaac
Author: srikanth.sundarrajan <sr...@inmobi.com>
Authored: Wed Apr 17 14:59:49 2013 +0530
Committer: srikanth.sundarrajan <sr...@inmobi.com>
Committed: Wed Apr 17 14:59:49 2013 +0530

----------------------------------------------------------------------
 .../org/apache/falcon/FalconRuntimException.java   |    2 +-
 .../falcon/cleanup/AbstractCleanupHandler.java     |   28 +-
 .../apache/falcon/cleanup/FeedCleanupHandler.java  |    3 +
 .../falcon/cleanup/ProcessCleanupHandler.java      |    3 +
 .../org/apache/falcon/entity/ClusterHelper.java    |    3 +
 .../apache/falcon/entity/ColoClusterRelation.java  |   27 +-
 .../entity/EntityNotRegisteredException.java       |    3 +
 .../java/org/apache/falcon/entity/EntityUtil.java  |  271 ++++++++-------
 .../java/org/apache/falcon/entity/ExternalId.java  |    3 +
 .../java/org/apache/falcon/entity/FeedHelper.java  |   11 +-
 .../org/apache/falcon/entity/ProcessHelper.java    |    8 +-
 .../apache/falcon/entity/WorkflowNameBuilder.java  |   11 +-
 .../apache/falcon/entity/common/Configuration.java |    3 +
 .../apache/falcon/entity/common/FeedDataPath.java  |   10 +-
 .../falcon/entity/parser/ClusterEntityParser.java  |    3 +
 .../entity/parser/CrossEntityValidations.java      |    8 +-
 .../apache/falcon/entity/parser/EntityParser.java  |   13 +-
 .../falcon/entity/parser/EntityParserFactory.java  |   18 +-
 .../falcon/entity/parser/FeedEntityParser.java     |   21 +-
 .../falcon/entity/parser/ValidationException.java  |    2 +-
 .../falcon/entity/store/ConfigurationStore.java    |   34 +-
 .../entity/store/EntityAlreadyExistsException.java |    3 +
 .../falcon/entity/store/StoreAccessException.java  |    3 +
 .../org/apache/falcon/entity/v0/EntityGraph.java   |   38 ++-
 .../falcon/entity/v0/EntityIntegrityChecker.java   |   19 +-
 .../apache/falcon/expression/ExpressionHelper.java |   47 ++--
 .../java/org/apache/falcon/group/FeedGroupMap.java |   11 +-
 .../org/apache/falcon/security/CurrentUser.java    |   18 +-
 .../apache/falcon/security/FalconLoginModule.java  |    7 +-
 .../apache/falcon/security/FalconPrincipal.java    |    3 +
 .../security/FalconSecurityConfiguration.java      |    3 +
 .../apache/falcon/security/SecurityConstants.java  |    7 +-
 .../service/ConfigurationChangeListener.java       |    3 +
 .../org/apache/falcon/service/FalconService.java   |    3 +
 .../apache/falcon/service/LogCleanupService.java   |    7 +-
 .../apache/falcon/service/ServiceInitializer.java  |    5 +-
 .../java/org/apache/falcon/service/Services.java   |   22 +-
 .../org/apache/falcon/update/UpdateHelper.java     |   87 ++---
 .../apache/falcon/util/ApplicationProperties.java  |   11 +-
 .../org/apache/falcon/util/BuildProperties.java    |   17 +-
 .../apache/falcon/util/DeploymentProperties.java   |   17 +-
 .../org/apache/falcon/util/DeploymentUtil.java     |   29 +-
 .../org/apache/falcon/util/ReflectionUtils.java    |    5 +
 .../org/apache/falcon/util/RuntimeProperties.java  |   23 +-
 .../org/apache/falcon/util/StartupProperties.java  |   16 +-
 .../apache/falcon/workflow/WorkflowBuilder.java    |    6 +-
 .../falcon/workflow/WorkflowEngineFactory.java     |    8 +-
 .../workflow/engine/AbstractWorkflowEngine.java    |   10 +-
 .../engine/WorkflowEngineActionListener.java       |    4 +
 .../falcon/cleanup/LogCleanupServiceTest.java      |   56 ++--
 .../org/apache/falcon/entity/AbstractTestBase.java |   46 ++--
 .../falcon/entity/ColoClusterRelationTest.java     |    3 +
 .../org/apache/falcon/entity/EntityTypeTest.java   |    3 +
 .../org/apache/falcon/entity/EntityUtilTest.java   |    3 +
 .../org/apache/falcon/entity/FeedHelperTest.java   |    3 +
 .../falcon/entity/TestWorkflowNameBuilder.java     |    5 +-
 .../entity/parser/ClusterEntityParserTest.java     |    3 +
 .../falcon/entity/parser/FeedEntityParserTest.java |   21 +-
 .../falcon/entity/parser/FeedUpdateTest.java       |   10 +-
 .../entity/parser/ProcessEntityParserTest.java     |   14 +-
 .../entity/store/ConfigurationStoreTest.java       |    5 +-
 .../apache/falcon/entity/v0/EntityGraphTest.java   |   11 +-
 .../org/apache/falcon/group/FeedGroupMapTest.java  |    3 +
 .../apache/falcon/security/CurrentUserTest.java    |    3 +
 .../org/apache/falcon/update/UpdateHelperTest.java |    9 +-
 .../apache/falcon/util/StartupPropertiesTest.java  |    3 +
 .../org/apache/falcon/logging/LogProvider.java     |    8 +-
 .../apache/falcon/converter/AbstractTestBase.java  |   34 +-
 .../falcon/rerun/handler/LateRerunHandler.java     |    2 +-
 69 files changed, 671 insertions(+), 491 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/FalconRuntimException.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/FalconRuntimException.java b/common/src/main/java/org/apache/falcon/FalconRuntimException.java
index b603fbf..e465f09 100644
--- a/common/src/main/java/org/apache/falcon/FalconRuntimException.java
+++ b/common/src/main/java/org/apache/falcon/FalconRuntimException.java
@@ -19,7 +19,7 @@
 package org.apache.falcon;
 
 /**
- * Runtime Execption class for Falcon application
+ * Runtime Exception class for Falcon application.
  */
 public class FalconRuntimException extends RuntimeException {
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/cleanup/AbstractCleanupHandler.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/cleanup/AbstractCleanupHandler.java b/common/src/main/java/org/apache/falcon/cleanup/AbstractCleanupHandler.java
index 264ea28..49662d1 100644
--- a/common/src/main/java/org/apache/falcon/cleanup/AbstractCleanupHandler.java
+++ b/common/src/main/java/org/apache/falcon/cleanup/AbstractCleanupHandler.java
@@ -38,20 +38,25 @@ import javax.servlet.jsp.el.ELException;
 import javax.servlet.jsp.el.ExpressionEvaluator;
 import java.io.IOException;
 
+/**
+ * Falcon cleanup handler for cleaning up work, temp and log files
+ * left behind by falcon.
+ */
 public abstract class AbstractCleanupHandler {
 
     protected static final Logger LOG = Logger
             .getLogger(AbstractCleanupHandler.class);
-    protected final ConfigurationStore STORE = ConfigurationStore.get();
+    protected static final ConfigurationStore STORE = ConfigurationStore.get();
     public static final ExpressionEvaluator EVALUATOR = new ExpressionEvaluatorImpl();
-    public static final ExpressionHelper resolver = ExpressionHelper.get();
+    public static final ExpressionHelper RESOLVER = ExpressionHelper.get();
 
     protected long getRetention(Entity entity, TimeUnit timeUnit)
-            throws FalconException {
+        throws FalconException {
+
         String retention = getRetentionValue(timeUnit);
         try {
             return (Long) EVALUATOR.evaluate("${" + retention + "}",
-                    Long.class, resolver, resolver);
+                    Long.class, RESOLVER, RESOLVER);
         } catch (ELException e) {
             throw new FalconException("Unable to evalue retention limit: "
                     + retention + " for entity: " + entity.getName());
@@ -64,9 +69,9 @@ public abstract class AbstractCleanupHandler {
 
     }
 
-    protected FileStatus[] getAllLogs(
-            org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
-            throws FalconException {
+    protected FileStatus[] getAllLogs(org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
+        throws FalconException {
+
         String stagingPath = ClusterHelper.getLocation(cluster, "staging");
         Path logPath = getLogPath(entity, stagingPath);
         FileSystem fs = getFileSystem(cluster);
@@ -79,9 +84,8 @@ public abstract class AbstractCleanupHandler {
         return paths;
     }
 
-    private FileSystem getFileSystem(
-            org.apache.falcon.entity.v0.cluster.Cluster cluster)
-            throws FalconException {
+    private FileSystem getFileSystem(org.apache.falcon.entity.v0.cluster.Cluster cluster)
+        throws FalconException {
 
         FileSystem fs;
         try {
@@ -94,7 +98,7 @@ public abstract class AbstractCleanupHandler {
     }
 
     protected void delete(Cluster cluster, Entity entity, long retention)
-            throws FalconException {
+        throws FalconException {
 
         FileStatus[] logs = getAllLogs(cluster, entity);
         long now = System.currentTimeMillis();
@@ -104,7 +108,7 @@ public abstract class AbstractCleanupHandler {
                 try {
                     boolean isDeleted = getFileSystem(cluster).delete(
                             log.getPath(), true);
-                    if (isDeleted == false) {
+                    if (!isDeleted) {
                         LOG.error("Unable to delete path: " + log.getPath());
                     } else {
                         LOG.info("Deleted path: " + log.getPath());

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/cleanup/FeedCleanupHandler.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/cleanup/FeedCleanupHandler.java b/common/src/main/java/org/apache/falcon/cleanup/FeedCleanupHandler.java
index 37fc653..0c8cf82 100644
--- a/common/src/main/java/org/apache/falcon/cleanup/FeedCleanupHandler.java
+++ b/common/src/main/java/org/apache/falcon/cleanup/FeedCleanupHandler.java
@@ -26,6 +26,9 @@ import org.apache.hadoop.fs.Path;
 
 import java.util.Collection;
 
+/**
+ * Cleanup files relating to feed management workflows.
+ */
 public class FeedCleanupHandler extends AbstractCleanupHandler {
 
     @Override

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/cleanup/ProcessCleanupHandler.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/cleanup/ProcessCleanupHandler.java b/common/src/main/java/org/apache/falcon/cleanup/ProcessCleanupHandler.java
index 9b96879..add1237 100644
--- a/common/src/main/java/org/apache/falcon/cleanup/ProcessCleanupHandler.java
+++ b/common/src/main/java/org/apache/falcon/cleanup/ProcessCleanupHandler.java
@@ -26,6 +26,9 @@ import org.apache.hadoop.fs.Path;
 
 import java.util.Collection;
 
+/**
+ * Handler to cleanup files left behind by falcon relating to process.
+ */
 public class ProcessCleanupHandler extends AbstractCleanupHandler {
 
     @Override

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/ClusterHelper.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/ClusterHelper.java b/common/src/main/java/org/apache/falcon/entity/ClusterHelper.java
index 3d77887..e332aba 100644
--- a/common/src/main/java/org/apache/falcon/entity/ClusterHelper.java
+++ b/common/src/main/java/org/apache/falcon/entity/ClusterHelper.java
@@ -22,6 +22,9 @@ import org.apache.falcon.entity.v0.cluster.*;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
 
+/**
+ * Helper to get end points relating to the cluster.
+ */
 public final class ClusterHelper {
     public static final String DEFAULT_BROKER_IMPL_CLASS = "org.apache.activemq.ActiveMQConnectionFactory";
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/ColoClusterRelation.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/ColoClusterRelation.java b/common/src/main/java/org/apache/falcon/entity/ColoClusterRelation.java
index 6c5d885..72dd952 100644
--- a/common/src/main/java/org/apache/falcon/entity/ColoClusterRelation.java
+++ b/common/src/main/java/org/apache/falcon/entity/ColoClusterRelation.java
@@ -28,21 +28,24 @@ import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-public class ColoClusterRelation implements ConfigurationChangeListener {
-    private static final ConcurrentHashMap<String, Set<String>> coloClusterMap
-            = new ConcurrentHashMap<String, Set<String>>();
-    private static final ColoClusterRelation instance = new ColoClusterRelation();
+/**
+ * Map of clusters in each colocation/ datacenter.
+ */
+public final class ColoClusterRelation implements ConfigurationChangeListener {
+    private static final ConcurrentHashMap<String, Set<String>> COLO_CLUSTER_MAP =
+        new ConcurrentHashMap<String, Set<String>>();
+    private static final ColoClusterRelation INSTANCE = new ColoClusterRelation();
 
     private ColoClusterRelation() {
     }
 
     public static ColoClusterRelation get() {
-        return instance;
+        return INSTANCE;
     }
 
     public Set<String> getClusters(String colo) {
-        if (coloClusterMap.containsKey(colo)) {
-            return coloClusterMap.get(colo);
+        if (COLO_CLUSTER_MAP.containsKey(colo)) {
+            return COLO_CLUSTER_MAP.get(colo);
         }
         return new HashSet<String>();
     }
@@ -54,8 +57,8 @@ public class ColoClusterRelation implements ConfigurationChangeListener {
         }
 
         Cluster cluster = (Cluster) entity;
-        coloClusterMap.putIfAbsent(cluster.getColo(), new HashSet<String>());
-        coloClusterMap.get(cluster.getColo()).add(cluster.getName());
+        COLO_CLUSTER_MAP.putIfAbsent(cluster.getColo(), new HashSet<String>());
+        COLO_CLUSTER_MAP.get(cluster.getColo()).add(cluster.getName());
     }
 
     @Override
@@ -65,9 +68,9 @@ public class ColoClusterRelation implements ConfigurationChangeListener {
         }
 
         Cluster cluster = (Cluster) entity;
-        coloClusterMap.get(cluster.getColo()).remove(cluster.getName());
-        if (coloClusterMap.get(cluster.getColo()).isEmpty()) {
-            coloClusterMap.remove(cluster.getColo());
+        COLO_CLUSTER_MAP.get(cluster.getColo()).remove(cluster.getName());
+        if (COLO_CLUSTER_MAP.get(cluster.getColo()).isEmpty()) {
+            COLO_CLUSTER_MAP.remove(cluster.getColo());
         }
     }
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/EntityNotRegisteredException.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/EntityNotRegisteredException.java b/common/src/main/java/org/apache/falcon/entity/EntityNotRegisteredException.java
index db922a4..40f83e4 100644
--- a/common/src/main/java/org/apache/falcon/entity/EntityNotRegisteredException.java
+++ b/common/src/main/java/org/apache/falcon/entity/EntityNotRegisteredException.java
@@ -20,6 +20,9 @@ package org.apache.falcon.entity;
 
 import org.apache.falcon.FalconException;
 
+/**
+ * Exception thrown by falcon when entity is not registered already in config store.
+ */
 public class EntityNotRegisteredException extends FalconException {
 
     public EntityNotRegisteredException(String message) {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/EntityUtil.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/EntityUtil.java b/common/src/main/java/org/apache/falcon/entity/EntityUtil.java
index f0ef515..ba086f8 100644
--- a/common/src/main/java/org/apache/falcon/entity/EntityUtil.java
+++ b/common/src/main/java/org/apache/falcon/entity/EntityUtil.java
@@ -44,12 +44,17 @@ import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.*;
 
-public class EntityUtil {
+/**
+ * Helper to get entity object.
+ */
+public final class EntityUtil {
     private static final long MINUTE_IN_MS = 60000L;
     private static final long HOUR_IN_MS = 3600000L;
     private static final long DAY_IN_MS = 86400000L;
     private static final long MONTH_IN_MS = 2592000000L;
 
+    private EntityUtil() {}
+
     public static <T extends Entity> T getEntity(EntityType type, String entityName) throws FalconException {
         ConfigurationStore configStore = ConfigurationStore.get();
         T entity = configStore.get(type, entityName);
@@ -233,19 +238,19 @@ public class EntityUtil {
 
         int count = 0;
         switch (frequency.getTimeUnit()) {
-            case months:
-                count = (int) ((now.getTime() - startTime.getTime()) / MONTH_IN_MS);
-                break;
-            case days:
-                count = (int) ((now.getTime() - startTime.getTime()) / DAY_IN_MS);
-                break;
-            case hours:
-                count = (int) ((now.getTime() - startTime.getTime()) / HOUR_IN_MS);
-                break;
-            case minutes:
-                count = (int) ((now.getTime() - startTime.getTime()) / MINUTE_IN_MS);
-                break;
-            default:
+        case months:
+            count = (int) ((now.getTime() - startTime.getTime()) / MONTH_IN_MS);
+            break;
+        case days:
+            count = (int) ((now.getTime() - startTime.getTime()) / DAY_IN_MS);
+            break;
+        case hours:
+            count = (int) ((now.getTime() - startTime.getTime()) / HOUR_IN_MS);
+            break;
+        case minutes:
+            count = (int) ((now.getTime() - startTime.getTime()) / MINUTE_IN_MS);
+            break;
+        default:
         }
 
         if (count > 2) {
@@ -268,19 +273,19 @@ public class EntityUtil {
 
         int count = 0;
         switch (frequency.getTimeUnit()) {
-            case months:
-                count = (int) ((instanceTime.getTime() - startTime.getTime()) / MONTH_IN_MS);
-                break;
-            case days:
-                count = (int) ((instanceTime.getTime() - startTime.getTime()) / DAY_IN_MS);
-                break;
-            case hours:
-                count = (int) ((instanceTime.getTime() - startTime.getTime()) / HOUR_IN_MS);
-                break;
-            case minutes:
-                count = (int) ((instanceTime.getTime() - startTime.getTime()) / MINUTE_IN_MS);
-                break;
-            default:
+        case months:
+            count = (int) ((instanceTime.getTime() - startTime.getTime()) / MONTH_IN_MS);
+            break;
+        case days:
+            count = (int) ((instanceTime.getTime() - startTime.getTime()) / DAY_IN_MS);
+            break;
+        case hours:
+            count = (int) ((instanceTime.getTime() - startTime.getTime()) / HOUR_IN_MS);
+            break;
+        case minutes:
+            count = (int) ((instanceTime.getTime() - startTime.getTime()) / MINUTE_IN_MS);
+            break;
+        default:
         }
 
         if (count > 2) {
@@ -340,7 +345,8 @@ public class EntityUtil {
 
     @SuppressWarnings("rawtypes")
     private static void mapToProperties(Object obj, String name, Map<String, String> propMap, String[] filterProps)
-            throws FalconException {
+        throws FalconException {
+
         if (obj == null) {
             return;
         }
@@ -429,36 +435,38 @@ public class EntityUtil {
 
     public static <T extends Entity> T getClusterView(T entity, String clusterName) {
         switch (entity.getEntityType()) {
-            case CLUSTER:
-                return entity;
-
-            case FEED:
-                Feed feed = (Feed) entity.clone();
-                Cluster feedCluster = FeedHelper.getCluster(feed, clusterName);
-                Iterator<Cluster> itr = feed.getClusters().getClusters().iterator();
-                while (itr.hasNext()) {
-                    Cluster cluster = itr.next();
-                    //In addition to retaining the required clster, retain the sources clusters if this is the target
-                    // cluster
-                    //1. Retain cluster if cluster n
-                    if (!(cluster.getName().equals(clusterName) ||
-                            (feedCluster.getType() == ClusterType.TARGET && cluster.getType() == ClusterType.SOURCE))) {
-                        itr.remove();
-                    }
+        case CLUSTER:
+            return entity;
+
+        case FEED:
+            Feed feed = (Feed) entity.copy();
+            Cluster feedCluster = FeedHelper.getCluster(feed, clusterName);
+            Iterator<Cluster> itr = feed.getClusters().getClusters().iterator();
+            while (itr.hasNext()) {
+                Cluster cluster = itr.next();
+                //In addition to retaining the required clster, retain the sources clusters if this is the target
+                // cluster
+                //1. Retain cluster if cluster n
+                if (!(cluster.getName().equals(clusterName)
+                        || (feedCluster.getType() == ClusterType.TARGET
+                        && cluster.getType() == ClusterType.SOURCE))) {
+                    itr.remove();
                 }
-                return (T) feed;
-
-            case PROCESS:
-                Process process = (Process) entity.clone();
-                Iterator<org.apache.falcon.entity.v0.process.Cluster> procItr
-                        = process.getClusters().getClusters().iterator();
-                while (procItr.hasNext()) {
-                    org.apache.falcon.entity.v0.process.Cluster cluster = procItr.next();
-                    if (!cluster.getName().equals(clusterName)) {
-                        procItr.remove();
-                    }
+            }
+            return (T) feed;
+
+        case PROCESS:
+            Process process = (Process) entity.copy();
+            Iterator<org.apache.falcon.entity.v0.process.Cluster> procItr =
+                process.getClusters().getClusters().iterator();
+            while (procItr.hasNext()) {
+                org.apache.falcon.entity.v0.process.Cluster cluster = procItr.next();
+                if (!cluster.getName().equals(clusterName)) {
+                    procItr.remove();
                 }
-                return (T) process;
+            }
+            return (T) process;
+        default:
         }
         throw new UnsupportedOperationException("Not supported for entity type " + entity.getEntityType());
     }
@@ -466,23 +474,24 @@ public class EntityUtil {
     public static Set<String> getClustersDefined(Entity entity) {
         Set<String> clusters = new HashSet<String>();
         switch (entity.getEntityType()) {
-            case CLUSTER:
-                clusters.add(entity.getName());
-                break;
-
-            case FEED:
-                Feed feed = (Feed) entity;
-                for (Cluster cluster : feed.getClusters().getClusters()) {
-                    clusters.add(cluster.getName());
-                }
-                break;
+        case CLUSTER:
+            clusters.add(entity.getName());
+            break;
+
+        case FEED:
+            Feed feed = (Feed) entity;
+            for (Cluster cluster : feed.getClusters().getClusters()) {
+                clusters.add(cluster.getName());
+            }
+            break;
 
-            case PROCESS:
-                Process process = (Process) entity;
-                for (org.apache.falcon.entity.v0.process.Cluster cluster : process.getClusters().getClusters()) {
-                    clusters.add(cluster.getName());
-                }
-                break;
+        case PROCESS:
+            Process process = (Process) entity;
+            for (org.apache.falcon.entity.v0.process.Cluster cluster : process.getClusters().getClusters()) {
+                clusters.add(cluster.getName());
+            }
+            break;
+        default:
         }
         return clusters;
     }
@@ -503,9 +512,33 @@ public class EntityUtil {
         return applicableClusters;
     }
 
-    public static Path getStagingPath(
-            org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
-            throws FalconException {
+    public static Retry getRetry(Entity entity) throws FalconException {
+        switch (entity.getEntityType()) {
+        case FEED:
+            if (!RuntimeProperties.get()
+                    .getProperty("feed.retry.allowed", "true")
+                    .equalsIgnoreCase("true")) {
+                return null;
+            }
+            Retry retry = new Retry();
+            retry.setAttempts(Integer.parseInt(RuntimeProperties.get()
+                    .getProperty("feed.retry.attempts", "3")));
+            retry.setDelay(new Frequency(RuntimeProperties.get().getProperty(
+                    "feed.retry.frequency", "minutes(5)")));
+            retry.setPolicy(PolicyType.fromValue(RuntimeProperties.get()
+                    .getProperty("feed.retry.policy", "exp-backoff")));
+            return retry;
+        case PROCESS:
+            Process process = (Process) entity;
+            return process.getRetry();
+        default:
+            throw new FalconException("Cannot create Retry for entity:" + entity.getName());
+        }
+    }
+
+    public static Path getStagingPath(org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
+        throws FalconException {
+
         try {
             return new Path(ClusterHelper.getLocation(cluster, "staging"),
                     EntityUtil.getStagingPath(entity));
@@ -514,67 +547,43 @@ public class EntityUtil {
         }
     }
 
-    public static Retry getRetry(Entity entity) throws FalconException {
-        switch (entity.getEntityType()) {
-            case FEED:
-                if (!RuntimeProperties.get()
-                        .getProperty("feed.retry.allowed", "true")
-                        .equalsIgnoreCase("true")) {
-                    return null;
-                }
-                Retry retry = new Retry();
-                retry.setAttempts(Integer.parseInt(RuntimeProperties.get()
-                        .getProperty("feed.retry.attempts", "3")));
-                retry.setDelay(new Frequency(RuntimeProperties.get().getProperty(
-                        "feed.retry.frequency", "minutes(5)")));
-                retry.setPolicy(PolicyType.fromValue(RuntimeProperties.get()
-                        .getProperty("feed.retry.policy", "exp-backoff")));
-                return retry;
-            case PROCESS:
-                Process process = (Process) entity;
-                return process.getRetry();
-            default:
-                throw new FalconException("Cannot create Retry for entity:" + entity.getName());
-        }
-    }
-
     public static LateProcess getLateProcess(Entity entity)
-            throws FalconException {
+        throws FalconException {
+
         switch (entity.getEntityType()) {
-            case FEED:
-                if (!RuntimeProperties.get()
-                        .getProperty("feed.late.allowed", "true")
-                        .equalsIgnoreCase("true")) {
-                    return null;
-                }
-                LateProcess lateProcess = new LateProcess();
-                lateProcess.setDelay(new Frequency(RuntimeProperties.get()
-                        .getProperty("feed.late.frequency", "hours(3)")));
-                lateProcess.setPolicy(PolicyType.fromValue(RuntimeProperties.get()
-                        .getProperty("feed.late.policy", "exp-backoff")));
-                LateInput lateInput = new LateInput();
-                lateInput.setInput(entity.getName());
-                //TODO - Assuming the late workflow is not used
-                lateInput.setWorkflowPath("ignore.xml");
-                lateProcess.getLateInputs().add(lateInput);
-                return lateProcess;
-            case PROCESS:
-                Process process = (Process) entity;
-                return process.getLateProcess();
-            default:
-                throw new FalconException("Cannot create Late Process for entity:" + entity.getName());
-        }
-    }
-
-    public static Path getLogPath(
-            org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
-            throws FalconException {
-        Path logPath = new Path(ClusterHelper.getLocation(cluster,
+        case FEED:
+            if (!RuntimeProperties.get()
+                    .getProperty("feed.late.allowed", "true")
+                    .equalsIgnoreCase("true")) {
+                return null;
+            }
+            LateProcess lateProcess = new LateProcess();
+            lateProcess.setDelay(new Frequency(RuntimeProperties.get()
+                    .getProperty("feed.late.frequency", "hours(3)")));
+            lateProcess.setPolicy(PolicyType.fromValue(RuntimeProperties.get()
+                    .getProperty("feed.late.policy", "exp-backoff")));
+            LateInput lateInput = new LateInput();
+            lateInput.setInput(entity.getName());
+            //TODO - Assuming the late workflow is not used
+            lateInput.setWorkflowPath("ignore.xml");
+            lateProcess.getLateInputs().add(lateInput);
+            return lateProcess;
+        case PROCESS:
+            Process process = (Process) entity;
+            return process.getLateProcess();
+        default:
+            throw new FalconException("Cannot create Late Process for entity:" + entity.getName());
+        }
+    }
+
+    public static Path getLogPath(org.apache.falcon.entity.v0.cluster.Cluster cluster, Entity entity)
+        throws FalconException {
+
+        return new Path(ClusterHelper.getLocation(cluster,
                 "staging"), EntityUtil.getStagingPath(entity) + "/../logs");
-        return logPath;
     }
 
-    public static String UTCtoURIDate(String utc) throws FalconException {
+    public static String fromUTCtoURIDate(String utc) throws FalconException {
         DateFormat utcFormat = new SimpleDateFormat(
                 "yyyy'-'MM'-'dd'T'HH':'mm'Z'");
         Date utcDate;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/ExternalId.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/ExternalId.java b/common/src/main/java/org/apache/falcon/entity/ExternalId.java
index cb865d2..c53d83a 100644
--- a/common/src/main/java/org/apache/falcon/entity/ExternalId.java
+++ b/common/src/main/java/org/apache/falcon/entity/ExternalId.java
@@ -25,6 +25,9 @@ import org.apache.falcon.entity.v0.SchemaHelper;
 
 import java.util.Date;
 
+/**
+ * External id as represented by workflow engine.
+ */
 public class ExternalId {
     private static final String SEPARATOR = "/";
     private String id;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/FeedHelper.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/FeedHelper.java b/common/src/main/java/org/apache/falcon/entity/FeedHelper.java
index 4a39d8c..c96120d 100644
--- a/common/src/main/java/org/apache/falcon/entity/FeedHelper.java
+++ b/common/src/main/java/org/apache/falcon/entity/FeedHelper.java
@@ -28,7 +28,13 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 
-public class FeedHelper {
+/**
+ * Feed entity helper methods.
+ */
+public final class FeedHelper {
+
+    private FeedHelper() {}
+
     public static Cluster getCluster(Feed feed, String clusterName) {
         for (Cluster cluster : feed.getClusters().getClusters()) {
             if (cluster.getName().equals(clusterName)) {
@@ -93,7 +99,8 @@ public class FeedHelper {
     }
 
     public static String evaluateClusterExp(org.apache.falcon.entity.v0.cluster.Cluster clusterEntity, String exp)
-            throws FalconException {
+        throws FalconException {
+
         Properties properties = loadClusterProperties(clusterEntity);
         ExpressionHelper expHelp = ExpressionHelper.get();
         expHelp.setPropertiesForVariable(properties);

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/ProcessHelper.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/ProcessHelper.java b/common/src/main/java/org/apache/falcon/entity/ProcessHelper.java
index 598f26e..dc5ae7a 100644
--- a/common/src/main/java/org/apache/falcon/entity/ProcessHelper.java
+++ b/common/src/main/java/org/apache/falcon/entity/ProcessHelper.java
@@ -21,7 +21,13 @@ package org.apache.falcon.entity;
 import org.apache.falcon.entity.v0.process.Cluster;
 import org.apache.falcon.entity.v0.process.Process;
 
-public class ProcessHelper {
+/**
+ * Helper methods for accessing process members.
+ */
+public final class ProcessHelper {
+
+    private ProcessHelper() {}
+
     public static Cluster getCluster(Process process, String clusterName) {
         for (Cluster cluster : process.getClusters().getClusters()) {
             if (cluster.getName().equals(clusterName)) {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/WorkflowNameBuilder.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/WorkflowNameBuilder.java b/common/src/main/java/org/apache/falcon/entity/WorkflowNameBuilder.java
index 4a636cd..a1216e7 100644
--- a/common/src/main/java/org/apache/falcon/entity/WorkflowNameBuilder.java
+++ b/common/src/main/java/org/apache/falcon/entity/WorkflowNameBuilder.java
@@ -26,10 +26,14 @@ import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * Convenient builder for workflow name.
+ * @param <T>
+ */
 public class WorkflowNameBuilder<T extends Entity> {
     private static final String PREFIX = "FALCON";
 
-    T entity;
+    private T entity;
     private Tag tag;
     private List<String> suffixes;
 
@@ -37,6 +41,7 @@ public class WorkflowNameBuilder<T extends Entity> {
         this.entity = entity;
     }
 
+    //SUSPEND CHECKSTYLE CHECK
     public void setTag(Tag tag) {
         this.tag = tag;
     }
@@ -44,6 +49,7 @@ public class WorkflowNameBuilder<T extends Entity> {
     public void setSuffixes(List<String> suffixes) {
         this.suffixes = suffixes;
     }
+    //RESUME CHECKSTYLE CHECK
 
     public WorkflowName getWorkflowName() {
         return new WorkflowName(PREFIX, entity.getEntityType().name(),
@@ -61,6 +67,9 @@ public class WorkflowNameBuilder<T extends Entity> {
                 : WorkflowName.getTagAndSuffixes(entity, workflowName).second;
     }
 
+    /**
+     * Workflow name.
+     */
     public static class WorkflowName {
         private static final String SEPARATOR = "_";
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/common/Configuration.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/common/Configuration.java b/common/src/main/java/org/apache/falcon/entity/common/Configuration.java
index 0e7e8f1..2e0e426 100644
--- a/common/src/main/java/org/apache/falcon/entity/common/Configuration.java
+++ b/common/src/main/java/org/apache/falcon/entity/common/Configuration.java
@@ -23,6 +23,9 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentHashMap;
 
+/**
+ * Property k/v.
+ */
 public class Configuration implements Iterable<Map.Entry<String, String>>, Cloneable {
 
     private final Map<String, String> properties;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/common/FeedDataPath.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/common/FeedDataPath.java b/common/src/main/java/org/apache/falcon/entity/common/FeedDataPath.java
index 470c98a..4031e14 100644
--- a/common/src/main/java/org/apache/falcon/entity/common/FeedDataPath.java
+++ b/common/src/main/java/org/apache/falcon/entity/common/FeedDataPath.java
@@ -19,8 +19,16 @@ package org.apache.falcon.entity.common;
 
 import java.util.regex.Pattern;
 
-public class FeedDataPath {
+/**
+ * Helper to map feed path and the time component.
+ */
+public final class FeedDataPath {
+
+    private FeedDataPath() {}
 
+    /**
+     * Standard variables for feed time components.
+     */
     public static enum VARS {
         YEAR("yyyy"), MONTH("MM"), DAY("dd"), HOUR("HH"), MINUTE("mm");
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/ClusterEntityParser.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/ClusterEntityParser.java b/common/src/main/java/org/apache/falcon/entity/parser/ClusterEntityParser.java
index c6ef988..8011dce 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/ClusterEntityParser.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/ClusterEntityParser.java
@@ -27,6 +27,9 @@ import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.log4j.Logger;
 
+/**
+ * Parser that parses cluster entity definition.
+ */
 public class ClusterEntityParser extends EntityParser<Cluster> {
 
     private static final Logger LOG = Logger.getLogger(ProcessEntityParser.class);

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/CrossEntityValidations.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/CrossEntityValidations.java b/common/src/main/java/org/apache/falcon/entity/parser/CrossEntityValidations.java
index 09aed24..d8d3d78 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/CrossEntityValidations.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/CrossEntityValidations.java
@@ -28,8 +28,13 @@ import org.apache.falcon.expression.ExpressionHelper;
 
 import java.util.Date;
 
+/**
+ * Validation helper functions to validate across process, feed and cluster definitions.
+ */
 public final class CrossEntityValidations {
 
+    private CrossEntityValidations() {}
+
     public static void validateInstanceRange(Process process, Input input, Feed feed) throws FalconException {
 
         try {
@@ -78,7 +83,8 @@ public final class CrossEntityValidations {
     }
 
     public static void validateFeedRetentionPeriod(String startInstance, Feed feed, String clusterName)
-            throws FalconException {
+        throws FalconException {
+
         String feedRetention = FeedHelper.getCluster(feed, clusterName).getRetention().getLimit().toString();
         ExpressionHelper evaluator = ExpressionHelper.get();
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/EntityParser.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/EntityParser.java b/common/src/main/java/org/apache/falcon/entity/parser/EntityParser.java
index 6b06cc4..d24fafc 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/EntityParser.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/EntityParser.java
@@ -31,10 +31,10 @@ import java.io.InputStream;
 import java.util.List;
 
 /**
- * Generic Abstract Entity Parser, the concrete FEED, PROCESS and CLUSTER
- * Should extend this parser to implement specific parsing.
+ * Generic Abstract Entity Parser, the concrete FEED, PROCESS and CLUSTER should extend this parser
+ * to implement specific parsing.
  *
- * @param <T>
+ * @param <T> of type Entity
  */
 public abstract class EntityParser<T extends Entity> {
 
@@ -42,11 +42,6 @@ public abstract class EntityParser<T extends Entity> {
 
     private final EntityType entityType;
 
-    /**
-     * Constructor
-     *
-     * @param entityType - can be FEED or PROCESS
-     */
     protected EntityParser(EntityType entityType) {
         this.entityType = entityType;
     }
@@ -69,7 +64,7 @@ public abstract class EntityParser<T extends Entity> {
     }
 
     /**
-     * Parses xml stream
+     * Parses xml stream.
      *
      * @param xmlStream
      * @return entity

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/EntityParserFactory.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/EntityParserFactory.java b/common/src/main/java/org/apache/falcon/entity/parser/EntityParserFactory.java
index 43542c3..5a33201 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/EntityParserFactory.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/EntityParserFactory.java
@@ -33,20 +33,20 @@ public final class EntityParserFactory {
      * unmarshalled easily by concrete classes based on the class type using
      * JAXB.
      *
-     * @param entityType
+     * @param entityType - entity type
      * @return concrete parser based on entity type
      */
     public static EntityParser getParser(final EntityType entityType) {
 
         switch (entityType) {
-            case PROCESS:
-                return new ProcessEntityParser();
-            case FEED:
-                return new FeedEntityParser();
-            case CLUSTER:
-                return new ClusterEntityParser();
-            default:
-                throw new IllegalArgumentException("Unhandled entity type: " + entityType);
+        case PROCESS:
+            return new ProcessEntityParser();
+        case FEED:
+            return new FeedEntityParser();
+        case CLUSTER:
+            return new ClusterEntityParser();
+        default:
+            throw new IllegalArgumentException("Unhandled entity type: " + entityType);
         }
     }
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/FeedEntityParser.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/FeedEntityParser.java b/common/src/main/java/org/apache/falcon/entity/parser/FeedEntityParser.java
index 475384e..1c323fd 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/FeedEntityParser.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/FeedEntityParser.java
@@ -43,6 +43,9 @@ import java.util.HashSet;
 import java.util.Set;
 import java.util.TimeZone;
 
+/**
+ * Parser that parses feed entity definition.
+ */
 public class FeedEntityParser extends EntityParser<Feed> {
 
     private static final Logger LOG = Logger.getLogger(FeedEntityParser.class);
@@ -112,20 +115,16 @@ public class FeedEntityParser extends EntityParser<Feed> {
                             cluster.getName()).getPath()).equals(
                     FeedGroup.getDatePattern(defaultPath))) {
                 throw new ValidationException("Feeds default path pattern: "
-                        + FeedHelper.getLocation(feed, LocationType.DATA)
-                        .getPath()
+                        + FeedHelper.getLocation(feed, LocationType.DATA).getPath()
                         + ", does not match with cluster: "
                         + cluster.getName()
                         + " path pattern: "
-                        + FeedHelper.getLocation(feed, LocationType.DATA,
-                        cluster.getName()).getPath());
+                        + FeedHelper.getLocation(feed, LocationType.DATA, cluster.getName()).getPath());
             }
         }
         for (String groupName : groupNames) {
             FeedGroup group = FeedGroupMap.get().getGroupsMapping().get(groupName);
-            if (group == null || group.canContainFeed(feed)) {
-                continue;
-            } else {
+            if (group != null && !group.canContainFeed(feed)) {
                 throw new ValidationException(
                         "Feed " + feed.getName() + "'s frequency: " + feed.getFrequency().toString()
                                 + ", path pattern: " + FeedHelper.getLocation(feed, LocationType.DATA).getPath()
@@ -242,8 +241,8 @@ public class FeedEntityParser extends EntityParser<Feed> {
                 String part = FeedHelper.normalizePartitionExpression(cluster.getPartition());
                 if (StringUtils.split(part, '/').length == 0) {
                     throw new ValidationException(
-                            "Partition expression has to be specified for cluster " + cluster.getName() +
-                                    " as there are more than one source clusters");
+                            "Partition expression has to be specified for cluster " + cluster.getName()
+                                    + " as there are more than one source clusters");
                 }
                 validateClusterExpDefined(cluster);
 
@@ -256,8 +255,8 @@ public class FeedEntityParser extends EntityParser<Feed> {
                         int numParts = StringUtils.split(part, '/').length;
                         if (numParts > feedParts) {
                             throw new ValidationException(
-                                    "Partition for " + src.getName() + " and " + cluster.getName() +
-                                            "clusters is more than the number of partitions defined in feed");
+                                    "Partition for " + src.getName() + " and " + cluster.getName()
+                                            + "clusters is more than the number of partitions defined in feed");
                         }
                     }
                 }

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/parser/ValidationException.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/parser/ValidationException.java b/common/src/main/java/org/apache/falcon/entity/parser/ValidationException.java
index e01a378..98f1cb9 100644
--- a/common/src/main/java/org/apache/falcon/entity/parser/ValidationException.java
+++ b/common/src/main/java/org/apache/falcon/entity/parser/ValidationException.java
@@ -21,7 +21,7 @@ package org.apache.falcon.entity.parser;
 import org.apache.falcon.FalconException;
 
 /**
- * ValidationException during parsing
+ * ValidationException during parsing.
  */
 public class ValidationException extends FalconException {
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/store/ConfigurationStore.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/store/ConfigurationStore.java b/common/src/main/java/org/apache/falcon/entity/store/ConfigurationStore.java
index 8fd3775..4897c25 100644
--- a/common/src/main/java/org/apache/falcon/entity/store/ConfigurationStore.java
+++ b/common/src/main/java/org/apache/falcon/entity/store/ConfigurationStore.java
@@ -37,27 +37,35 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
-import java.util.*;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-public class ConfigurationStore implements FalconService {
+/**
+ * Persistent store for falcon entities.
+ */
+public final class ConfigurationStore implements FalconService {
 
     private static final Logger LOG = Logger.getLogger(ConfigurationStore.class);
     private static final Logger AUDIT = Logger.getLogger("AUDIT");
     private static final String UTF_8 = "UTF-8";
 
-    private static final ConfigurationStore store = new ConfigurationStore();
+    private static final ConfigurationStore STORE = new ConfigurationStore();
 
     private Set<ConfigurationChangeListener> listeners = new LinkedHashSet<ConfigurationChangeListener>();
 
     private ThreadLocal<Entity> updatesInProgress = new ThreadLocal<Entity>();
 
     public static ConfigurationStore get() {
-        return store;
+        return STORE;
     }
 
     private final Map<EntityType, ConcurrentHashMap<String, Entity>> dictionary
-            = new HashMap<EntityType, ConcurrentHashMap<String, Entity>>();
+        = new HashMap<EntityType, ConcurrentHashMap<String, Entity>>();
 
     private final FileSystem fs;
     private final Path storePath;
@@ -69,15 +77,9 @@ public class ConfigurationStore implements FalconService {
         }
     };
 
-    @SuppressWarnings("unchecked")
     private ConfigurationStore() {
-        Class<? extends Entity>[] entityClasses = new Class[EntityType.values().length];
-
-        int index = 0;
-
         for (EntityType type : EntityType.values()) {
             dictionary.put(type, new ConcurrentHashMap<String, Entity>());
-            entityClasses[index++] = type.getEntityClass();
         }
 
         String uri = StartupProperties.get().getProperty("config.store.uri");
@@ -221,7 +223,7 @@ public class ConfigurationStore implements FalconService {
             T entity = (T) entityMap.get(name);
             if (entity == NULL) { // Object equality being checked
                 try {
-                    entity = this.<T>restore(type, name);
+                    entity = this.restore(type, name);
                 } catch (IOException e) {
                     throw new StoreAccessException(e);
                 }
@@ -240,7 +242,7 @@ public class ConfigurationStore implements FalconService {
     }
 
     /**
-     * Remove an entity which is already stored in the config store
+     * Remove an entity which is already stored in the config store.
      *
      * @param type - Entity type being removed
      * @param name - Name of the entity object being removed
@@ -283,7 +285,7 @@ public class ConfigurationStore implements FalconService {
      * @return - Array of entity types
      */
     public Entity[] search(EntityType type, String... keywords) {
-        return null;// TODO
+        return null;
     }
 
     /**
@@ -310,7 +312,7 @@ public class ConfigurationStore implements FalconService {
     }
 
     /**
-     * Archive removed configuration in the persistent store
+     * Archive removed configuration in the persistent store.
      *
      * @param type - Entity type to archive
      * @param name - name
@@ -335,7 +337,7 @@ public class ConfigurationStore implements FalconService {
      */
     @SuppressWarnings("unchecked")
     private synchronized <T extends Entity> T restore(EntityType type, String name)
-            throws IOException, FalconException {
+        throws IOException, FalconException {
 
         InputStream in = fs.open(new Path(storePath, type + Path.SEPARATOR + URLEncoder.encode(name, UTF_8) + ".xml"));
         try {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/store/EntityAlreadyExistsException.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/store/EntityAlreadyExistsException.java b/common/src/main/java/org/apache/falcon/entity/store/EntityAlreadyExistsException.java
index ce550d4..28c5ac0 100644
--- a/common/src/main/java/org/apache/falcon/entity/store/EntityAlreadyExistsException.java
+++ b/common/src/main/java/org/apache/falcon/entity/store/EntityAlreadyExistsException.java
@@ -20,6 +20,9 @@ package org.apache.falcon.entity.store;
 
 import org.apache.falcon.FalconException;
 
+/**
+ * Exception to thrown when entity being sought for addition is already present in config store.
+ */
 public class EntityAlreadyExistsException extends FalconException {
 
     public EntityAlreadyExistsException(Exception e) {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/store/StoreAccessException.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/store/StoreAccessException.java b/common/src/main/java/org/apache/falcon/entity/store/StoreAccessException.java
index a231242..318dc2e 100644
--- a/common/src/main/java/org/apache/falcon/entity/store/StoreAccessException.java
+++ b/common/src/main/java/org/apache/falcon/entity/store/StoreAccessException.java
@@ -20,6 +20,9 @@ package org.apache.falcon.entity.store;
 
 import org.apache.falcon.FalconException;
 
+/**
+ * Exception when there in issue accessing the persistent store.
+ */
 public class StoreAccessException extends FalconException {
 
     /**

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/v0/EntityGraph.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/v0/EntityGraph.java b/common/src/main/java/org/apache/falcon/entity/v0/EntityGraph.java
index f2b66e5..803fa9e 100644
--- a/common/src/main/java/org/apache/falcon/entity/v0/EntityGraph.java
+++ b/common/src/main/java/org/apache/falcon/entity/v0/EntityGraph.java
@@ -34,9 +34,12 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-public class EntityGraph implements ConfigurationChangeListener {
+/**
+ * An in-memory graph of entities and relationship among themselves.
+ */
+public final class EntityGraph implements ConfigurationChangeListener {
 
-    private static Logger LOG = Logger.getLogger(EntityGraph.class);
+    private static final Logger LOG = Logger.getLogger(EntityGraph.class);
 
     private static EntityGraph instance = new EntityGraph();
 
@@ -69,12 +72,13 @@ public class EntityGraph implements ConfigurationChangeListener {
     public void onAdd(Entity entity) throws FalconException {
         Map<Node, Set<Node>> nodeEdges = null;
         switch (entity.getEntityType()) {
-            case PROCESS:
-                nodeEdges = getEdgesFor((Process) entity);
-                break;
-            case FEED:
-                nodeEdges = getEdgesFor((Feed) entity);
-                break;
+        case PROCESS:
+            nodeEdges = getEdgesFor((Process) entity);
+            break;
+        case FEED:
+            nodeEdges = getEdgesFor((Feed) entity);
+            break;
+        default:
         }
         if (nodeEdges == null) {
             return;
@@ -95,12 +99,13 @@ public class EntityGraph implements ConfigurationChangeListener {
     public void onRemove(Entity entity) throws FalconException {
         Map<Node, Set<Node>> nodeEdges = null;
         switch (entity.getEntityType()) {
-            case PROCESS:
-                nodeEdges = getEdgesFor((Process) entity);
-                break;
-            case FEED:
-                nodeEdges = getEdgesFor((Feed) entity);
-                break;
+        case PROCESS:
+            nodeEdges = getEdgesFor((Process) entity);
+            break;
+        case FEED:
+            nodeEdges = getEdgesFor((Feed) entity);
+            break;
+        default:
         }
         if (nodeEdges == null) {
             return;
@@ -178,7 +183,10 @@ public class EntityGraph implements ConfigurationChangeListener {
         return nodeEdges;
     }
 
-    private static class Node {
+    /**
+     * Node element in the graph.
+     */
+    private static final class Node {
 
         private final EntityType type;
         private final String name;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/entity/v0/EntityIntegrityChecker.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/entity/v0/EntityIntegrityChecker.java b/common/src/main/java/org/apache/falcon/entity/v0/EntityIntegrityChecker.java
index b523c8b..bd32852 100644
--- a/common/src/main/java/org/apache/falcon/entity/v0/EntityIntegrityChecker.java
+++ b/common/src/main/java/org/apache/falcon/entity/v0/EntityIntegrityChecker.java
@@ -26,7 +26,12 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 
-public class EntityIntegrityChecker {
+/**
+ * Helper methods to check integrity of entity.
+ */
+public final class EntityIntegrityChecker {
+
+    private EntityIntegrityChecker() {}
 
     public static Pair<String, EntityType>[] referencedBy(Entity entity) throws FalconException {
         Set<Entity> deps = EntityGraph.get().getDependents(entity);
@@ -35,14 +40,14 @@ public class EntityIntegrityChecker {
         }
 
         switch (entity.getEntityType()) {
-            case CLUSTER:
-                return filter(deps, EntityType.FEED, EntityType.PROCESS);
+        case CLUSTER:
+            return filter(deps, EntityType.FEED, EntityType.PROCESS);
 
-            case FEED:
-                return filter(deps, EntityType.PROCESS);
+        case FEED:
+            return filter(deps, EntityType.PROCESS);
 
-            default:
-                return null;
+        default:
+            return null;
         }
     }
 

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/expression/ExpressionHelper.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/expression/ExpressionHelper.java b/common/src/main/java/org/apache/falcon/expression/ExpressionHelper.java
index f57ef95..5d70933 100644
--- a/common/src/main/java/org/apache/falcon/expression/ExpressionHelper.java
+++ b/common/src/main/java/org/apache/falcon/expression/ExpressionHelper.java
@@ -34,19 +34,22 @@ import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * Helper for evaluating expressions.
+ */
 public final class ExpressionHelper implements FunctionMapper, VariableResolver {
 
-    private static final ExpressionHelper instance = new ExpressionHelper();
+    private static final ExpressionHelper INSTANCE = new ExpressionHelper();
 
     private ThreadLocal<Properties> threadVariables = new ThreadLocal<Properties>();
 
-    private static final Pattern sysPropertyPattern = Pattern.compile("\\$\\{[A-Za-z0-9_.]+\\}");
+    private static final Pattern SYS_PROPERTY_PATTERN = Pattern.compile("\\$\\{[A-Za-z0-9_.]+\\}");
 
     private static final ExpressionEvaluator EVALUATOR = new ExpressionEvaluatorImpl();
-    private static final ExpressionHelper resolver = ExpressionHelper.get();
+    private static final ExpressionHelper RESOLVER = ExpressionHelper.get();
 
     public static ExpressionHelper get() {
-        return instance;
+        return INSTANCE;
     }
 
     private ExpressionHelper() {
@@ -59,7 +62,7 @@ public final class ExpressionHelper implements FunctionMapper, VariableResolver
     @SuppressWarnings("unchecked")
     public <T> T evaluateFullExpression(String expression, Class<T> clazz) throws FalconException {
         try {
-            return (T) EVALUATOR.evaluate(expression, clazz, resolver, resolver);
+            return (T) EVALUATOR.evaluate(expression, clazz, RESOLVER, RESOLVER);
         } catch (ELException e) {
             throw new FalconException("Unable to evaluate " + expression, e);
         }
@@ -94,21 +97,21 @@ public final class ExpressionHelper implements FunctionMapper, VariableResolver
         Calendar dsInstanceCal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
         dsInstanceCal.setTime(date);
         switch (boundary) {
-            case Calendar.YEAR:
-                dsInstanceCal.set(Calendar.MONTH, 0);
-            case Calendar.MONTH:
-                dsInstanceCal.set(Calendar.DAY_OF_MONTH, 1);
-            case Calendar.DAY_OF_MONTH:
-                dsInstanceCal.set(Calendar.HOUR_OF_DAY, 0);
-            case Calendar.HOUR:
-                dsInstanceCal.set(Calendar.MINUTE, 0);
-                dsInstanceCal.set(Calendar.SECOND, 0);
-                dsInstanceCal.set(Calendar.MILLISECOND, 0);
-                break;
-            case Calendar.SECOND:
-                break;
-            default:
-                throw new IllegalArgumentException("Invalid boundary " + boundary);
+        case Calendar.YEAR:
+            dsInstanceCal.set(Calendar.MONTH, 0);
+        case Calendar.MONTH:
+            dsInstanceCal.set(Calendar.DAY_OF_MONTH, 1);
+        case Calendar.DAY_OF_MONTH:
+            dsInstanceCal.set(Calendar.HOUR_OF_DAY, 0);
+        case Calendar.HOUR:
+            dsInstanceCal.set(Calendar.MINUTE, 0);
+            dsInstanceCal.set(Calendar.SECOND, 0);
+            dsInstanceCal.set(Calendar.MILLISECOND, 0);
+            break;
+        case Calendar.SECOND:
+            break;
+        default:
+            throw new IllegalArgumentException("Invalid boundary " + boundary);
         }
 
         dsInstanceCal.add(Calendar.YEAR, 0);
@@ -182,7 +185,7 @@ public final class ExpressionHelper implements FunctionMapper, VariableResolver
     }
 
     public static String substitute(String originalValue, Properties properties) {
-        Matcher envVarMatcher = sysPropertyPattern.matcher(originalValue);
+        Matcher envVarMatcher = SYS_PROPERTY_PATTERN.matcher(originalValue);
         while (envVarMatcher.find()) {
             String envVar = originalValue.substring(envVarMatcher.start() + 2,
                     envVarMatcher.end() - 1);
@@ -191,7 +194,7 @@ public final class ExpressionHelper implements FunctionMapper, VariableResolver
             envVar = "\\$\\{" + envVar + "\\}";
             if (envVal != null) {
                 originalValue = originalValue.replaceAll(envVar, Matcher.quoteReplacement(envVal));
-                envVarMatcher = sysPropertyPattern.matcher(originalValue);
+                envVarMatcher = SYS_PROPERTY_PATTERN.matcher(originalValue);
             }
         }
         return originalValue;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/group/FeedGroupMap.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/group/FeedGroupMap.java b/common/src/main/java/org/apache/falcon/group/FeedGroupMap.java
index 532392f..ed44b48 100644
--- a/common/src/main/java/org/apache/falcon/group/FeedGroupMap.java
+++ b/common/src/main/java/org/apache/falcon/group/FeedGroupMap.java
@@ -34,11 +34,11 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
- * Has 2 way mappings from feed to group and group to feed
+ * Has 2 way mappings from feed to group and group to feed.
  */
-public class FeedGroupMap implements ConfigurationChangeListener {
+public final class FeedGroupMap implements ConfigurationChangeListener {
 
-    private static final FeedGroupMap instance = new FeedGroupMap();
+    private static final FeedGroupMap INSTANCE = new FeedGroupMap();
     private Map<String, FeedGroup> groupsMapping = new ConcurrentHashMap<String, FeedGroup>();
 
     private FeedGroupMap() {
@@ -46,7 +46,7 @@ public class FeedGroupMap implements ConfigurationChangeListener {
     }
 
     public static FeedGroupMap get() {
-        return instance;
+        return INSTANCE;
     }
 
     public Map<String, FeedGroup> getGroupsMapping() {
@@ -88,7 +88,8 @@ public class FeedGroupMap implements ConfigurationChangeListener {
 
     @Override
     public void onChange(Entity oldEntity, Entity newEntity)
-            throws FalconException {
+        throws FalconException {
+
         onRemove(oldEntity);
         onAdd(newEntity);
     }

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/security/CurrentUser.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/security/CurrentUser.java b/common/src/main/java/org/apache/falcon/security/CurrentUser.java
index 9a3086c..4d2299e 100644
--- a/common/src/main/java/org/apache/falcon/security/CurrentUser.java
+++ b/common/src/main/java/org/apache/falcon/security/CurrentUser.java
@@ -22,14 +22,19 @@ import org.apache.log4j.Logger;
 
 import javax.security.auth.Subject;
 
+/**
+ * Current authenticated user via REST.
+ */
 public final class CurrentUser {
 
-    private static Logger LOG = Logger.getLogger(CurrentUser.class);
+    private static final Logger LOG = Logger.getLogger(CurrentUser.class);
+
+    private static final CurrentUser INSTANCE = new CurrentUser();
 
-    private static final CurrentUser instance = new CurrentUser();
+    private CurrentUser() {}
 
     public static CurrentUser get() {
-        return instance;
+        return INSTANCE;
     }
 
     private final ThreadLocal<Subject> currentSubject =
@@ -37,8 +42,7 @@ public final class CurrentUser {
 
     public static void authenticate(String user) {
         if (user == null || user.isEmpty()) {
-            throw new IllegalStateException
-                    ("Bad user name sent for authentication");
+            throw new IllegalStateException("Bad user name sent for authentication");
         }
         if (user.equals(getUserInternal())) {
             return;
@@ -47,11 +51,11 @@ public final class CurrentUser {
         Subject subject = new Subject();
         subject.getPrincipals().add(new FalconPrincipal(user));
         LOG.info("Logging in " + user);
-        instance.currentSubject.set(subject);
+        INSTANCE.currentSubject.set(subject);
     }
 
     public static Subject getSubject() {
-        return instance.currentSubject.get();
+        return INSTANCE.currentSubject.get();
     }
 
     public static String getUser() {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/security/FalconLoginModule.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/security/FalconLoginModule.java b/common/src/main/java/org/apache/falcon/security/FalconLoginModule.java
index a27a342..4f4542c 100644
--- a/common/src/main/java/org/apache/falcon/security/FalconLoginModule.java
+++ b/common/src/main/java/org/apache/falcon/security/FalconLoginModule.java
@@ -29,8 +29,11 @@ import javax.security.auth.spi.LoginModule;
 import java.security.Principal;
 import java.util.Map;
 
+/**
+ * Falcon JAAS login module.
+ */
 public class FalconLoginModule implements LoginModule {
-    private static Logger LOG = Logger.getLogger(FalconLoginModule.class);
+    private static final Logger LOG = Logger.getLogger(FalconLoginModule.class);
 
     private Subject subject;
 
@@ -62,11 +65,13 @@ public class FalconLoginModule implements LoginModule {
         throw new LoginException("No such user " + subject);
     }
 
+    //SUSPEND CHECKSTYLE CHECK
     @Override
     public void initialize(Subject subject, CallbackHandler callbackHandler,
                            Map<String, ?> sharedState, Map<String, ?> options) {
         this.subject = subject;
     }
+    //RESUME CHECKSTYLE CHECK
 
     @Override
     public boolean login() throws LoginException {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/security/FalconPrincipal.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/security/FalconPrincipal.java b/common/src/main/java/org/apache/falcon/security/FalconPrincipal.java
index bd27e23..ab93e1a 100644
--- a/common/src/main/java/org/apache/falcon/security/FalconPrincipal.java
+++ b/common/src/main/java/org/apache/falcon/security/FalconPrincipal.java
@@ -20,6 +20,9 @@ package org.apache.falcon.security;
 
 import java.security.Principal;
 
+/**
+ * Falcon JAAS principal object.
+ */
 public class FalconPrincipal implements Principal {
 
     private final String user;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/security/FalconSecurityConfiguration.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/security/FalconSecurityConfiguration.java b/common/src/main/java/org/apache/falcon/security/FalconSecurityConfiguration.java
index 20ec8df..7689672 100644
--- a/common/src/main/java/org/apache/falcon/security/FalconSecurityConfiguration.java
+++ b/common/src/main/java/org/apache/falcon/security/FalconSecurityConfiguration.java
@@ -22,6 +22,9 @@ import javax.security.auth.login.AppConfigurationEntry;
 import javax.security.auth.login.Configuration;
 import java.util.HashMap;
 
+/**
+ * Falcon JAAS security configuration.
+ */
 public class FalconSecurityConfiguration extends Configuration {
 
     private static final AppConfigurationEntry OS_SPECIFIC_LOGIN =

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/security/SecurityConstants.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/security/SecurityConstants.java b/common/src/main/java/org/apache/falcon/security/SecurityConstants.java
index b4f060f..8f7ba4a 100644
--- a/common/src/main/java/org/apache/falcon/security/SecurityConstants.java
+++ b/common/src/main/java/org/apache/falcon/security/SecurityConstants.java
@@ -22,7 +22,12 @@ import com.sun.security.auth.UnixPrincipal;
 
 import java.security.Principal;
 
-public class SecurityConstants {
+/**
+ * Constants for the security module.
+ */
+public final class SecurityConstants {
+
+    private SecurityConstants() {}
 
     public static final String OS_LOGIN_MODULE_NAME =
             "com.sun.security.auth.module.UnixLoginModule";

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/service/ConfigurationChangeListener.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/service/ConfigurationChangeListener.java b/common/src/main/java/org/apache/falcon/service/ConfigurationChangeListener.java
index 65621cb..56953ad 100644
--- a/common/src/main/java/org/apache/falcon/service/ConfigurationChangeListener.java
+++ b/common/src/main/java/org/apache/falcon/service/ConfigurationChangeListener.java
@@ -21,6 +21,9 @@ package org.apache.falcon.service;
 import org.apache.falcon.FalconException;
 import org.apache.falcon.entity.v0.Entity;
 
+/**
+ * Configuration change notification listener.
+ */
 public interface ConfigurationChangeListener {
 
     void onAdd(Entity entity) throws FalconException;

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/service/FalconService.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/service/FalconService.java b/common/src/main/java/org/apache/falcon/service/FalconService.java
index 049032b..a1eb8e0 100644
--- a/common/src/main/java/org/apache/falcon/service/FalconService.java
+++ b/common/src/main/java/org/apache/falcon/service/FalconService.java
@@ -20,6 +20,9 @@ package org.apache.falcon.service;
 
 import org.apache.falcon.FalconException;
 
+/**
+ * Falcon service initialized at startup.
+ */
 public interface FalconService {
 
     String getName();

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/service/LogCleanupService.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/service/LogCleanupService.java b/common/src/main/java/org/apache/falcon/service/LogCleanupService.java
index 17d5926..778be11 100644
--- a/common/src/main/java/org/apache/falcon/service/LogCleanupService.java
+++ b/common/src/main/java/org/apache/falcon/service/LogCleanupService.java
@@ -33,10 +33,13 @@ import java.util.Date;
 import java.util.Timer;
 import java.util.TimerTask;
 
+/**
+ * Log cleanup service.
+ */
 public class LogCleanupService implements FalconService {
 
     private static final Logger LOG = Logger.getLogger(LogCleanupService.class);
-    private final ExpressionEvaluator EVALUATOR = new ExpressionEvaluatorImpl();
+    private final ExpressionEvaluator evaluator = new ExpressionEvaluatorImpl();
     private final ExpressionHelper resolver = ExpressionHelper.get();
 
     @Override
@@ -80,7 +83,7 @@ public class LogCleanupService implements FalconService {
         String delay = StartupProperties.get().getProperty(
                 "falcon.cleanup.service.frequency", "days(1)");
         try {
-            return (Long) EVALUATOR.evaluate("${" + delay + "}", Long.class,
+            return (Long) evaluator.evaluate("${" + delay + "}", Long.class,
                     resolver, resolver);
         } catch (ELException e) {
             throw new FalconException("Exception in EL evaluation", e);

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/service/ServiceInitializer.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/service/ServiceInitializer.java b/common/src/main/java/org/apache/falcon/service/ServiceInitializer.java
index 466cb81..5e0256e 100644
--- a/common/src/main/java/org/apache/falcon/service/ServiceInitializer.java
+++ b/common/src/main/java/org/apache/falcon/service/ServiceInitializer.java
@@ -23,9 +23,12 @@ import org.apache.falcon.util.ReflectionUtils;
 import org.apache.falcon.util.StartupProperties;
 import org.apache.log4j.Logger;
 
+/**
+ * Initializer that Falcon uses at startup to bring up all the falcon startup services.
+ */
 public class ServiceInitializer {
 
-    private static Logger LOG = Logger.getLogger(ServiceInitializer.class);
+    private static final Logger LOG = Logger.getLogger(ServiceInitializer.class);
     private final Services services = Services.get();
 
     public void initialize() throws FalconException {

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/service/Services.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/service/Services.java b/common/src/main/java/org/apache/falcon/service/Services.java
index 955e906..6659ccd 100644
--- a/common/src/main/java/org/apache/falcon/service/Services.java
+++ b/common/src/main/java/org/apache/falcon/service/Services.java
@@ -20,34 +20,34 @@ package org.apache.falcon.service;
 
 import org.apache.falcon.FalconException;
 import org.apache.falcon.util.ReflectionUtils;
-import org.apache.log4j.Logger;
 
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.NoSuchElementException;
 
-
+/**
+ * Repository of services initialized at startup.
+ */
 public final class Services implements Iterable<FalconService> {
-    private static final Logger LOG = Logger.getLogger(Services.class);
 
-    private static Services instance = new Services();
+    private static final Services INSTANCE = new Services();
 
     private Services() {
     }
 
     public static Services get() {
-        return instance;
+        return INSTANCE;
     }
 
     private final Map<String, FalconService> services =
             new LinkedHashMap<String, FalconService>();
 
     public synchronized void register(FalconService service)
-            throws FalconException {
+        throws FalconException {
+
         if (services.containsKey(service.getName())) {
-            throw new FalconException("Service " + service.getName() +
-                    " already registered");
+            throw new FalconException("Service " + service.getName() + " already registered");
         } else {
             services.put(service.getName(), service);
         }
@@ -58,8 +58,7 @@ public final class Services implements Iterable<FalconService> {
         if (services.containsKey(serviceName)) {
             return (T) services.get(serviceName);
         } else {
-            throw new NoSuchElementException("Service " + serviceName +
-                    " not registered with registry");
+            throw new NoSuchElementException("Service " + serviceName + " not registered with registry");
         }
     }
 
@@ -74,8 +73,7 @@ public final class Services implements Iterable<FalconService> {
 
     public FalconService init(String serviceName) throws FalconException {
         if (isRegistered(serviceName)) {
-            throw new FalconException("Service is already initialized " +
-                    serviceName);
+            throw new FalconException("Service is already initialized " + serviceName);
         }
         FalconService service = ReflectionUtils.getInstance(serviceName + ".impl");
         register(service);

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/update/UpdateHelper.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/update/UpdateHelper.java b/common/src/main/java/org/apache/falcon/update/UpdateHelper.java
index 4e199da..a9d39de 100644
--- a/common/src/main/java/org/apache/falcon/update/UpdateHelper.java
+++ b/common/src/main/java/org/apache/falcon/update/UpdateHelper.java
@@ -36,37 +36,39 @@ import org.apache.log4j.Logger;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Helper methods to facilitate entity updates.
+ */
 public final class UpdateHelper {
     private static final Logger LOG = Logger.getLogger(UpdateHelper.class);
+
     private static final String[] FEED_FIELDS = new String[]{"partitions", "groups", "lateArrival.cutOff",
                                                              "schema.location", "schema.provider",
-                                                             "ACL.group", "ACL.owner", "ACL.permission"};
+                                                             "ACL.group", "ACL.owner", "ACL.permission", };
     private static final String[] PROCESS_FIELDS = new String[]{"retry.policy", "retry.delay", "retry.attempts",
                                                                 "lateProcess.policy", "lateProcess.delay",
                                                                 "lateProcess.lateInputs[\\d+].input",
-                                                                "lateProcess.lateInputs[\\d+].workflowPath"};
+                                                                "lateProcess.lateInputs[\\d+].workflowPath", };
+
+    private UpdateHelper() {}
 
     public static boolean shouldUpdate(Entity oldEntity, Entity newEntity, String cluster) throws FalconException {
         Entity oldView = EntityUtil.getClusterView(oldEntity, cluster);
         Entity newView = EntityUtil.getClusterView(newEntity, cluster);
         switch (oldEntity.getEntityType()) {
-            case FEED:
-                if (EntityUtil.equals(oldView, newView, FEED_FIELDS)) {
-                    return false;
-                }
-                return true;
+        case FEED:
+            return !EntityUtil.equals(oldView, newView, FEED_FIELDS);
 
-            case PROCESS:
-                if (EntityUtil.equals(oldView, newView, PROCESS_FIELDS)) {
-                    return false;
-                }
-                return true;
+        case PROCESS:
+            return !EntityUtil.equals(oldView, newView, PROCESS_FIELDS);
+        default:
         }
         throw new IllegalArgumentException("Unhandled entity type " + oldEntity.getEntityType());
     }
 
     public static boolean shouldUpdate(Entity oldEntity, Entity newEntity, Entity affectedEntity)
-            throws FalconException {
+        throws FalconException {
+
         if (oldEntity.getEntityType() == EntityType.FEED && affectedEntity.getEntityType() == EntityType.PROCESS) {
             return shouldUpdate((Feed) oldEntity, (Feed) newEntity, (Process) affectedEntity);
         } else {
@@ -77,26 +79,14 @@ public final class UpdateHelper {
     }
 
     public static boolean shouldUpdate(Feed oldFeed, Feed newFeed, Process affectedProcess) {
-        if (!FeedHelper
-                .getLocation(oldFeed.getLocations(), LocationType.DATA)
-                .getPath()
-                .equals(FeedHelper.getLocation(newFeed.getLocations(),
-                        LocationType.DATA).getPath())
-                || !FeedHelper
-                .getLocation(oldFeed.getLocations(), LocationType.META)
-                .getPath()
-                .equals(FeedHelper.getLocation(newFeed.getLocations(),
-                        LocationType.META).getPath())
-                || !FeedHelper
-                .getLocation(oldFeed.getLocations(), LocationType.STATS)
-                .getPath()
-                .equals(FeedHelper.getLocation(newFeed.getLocations(),
-                        LocationType.STATS).getPath())
-                || !FeedHelper
-                .getLocation(oldFeed.getLocations(), LocationType.TMP)
-                .getPath()
-                .equals(FeedHelper.getLocation(newFeed.getLocations(),
-                        LocationType.TMP).getPath())) {
+        if (!FeedHelper.getLocation(oldFeed.getLocations(), LocationType.DATA)
+            .getPath().equals(FeedHelper.getLocation(newFeed.getLocations(), LocationType.DATA).getPath())
+                || !FeedHelper.getLocation(oldFeed.getLocations(), LocationType.META)
+                    .getPath().equals(FeedHelper.getLocation(newFeed.getLocations(), LocationType.META).getPath())
+                || !FeedHelper.getLocation(oldFeed.getLocations(), LocationType.STATS)
+                    .getPath().equals(FeedHelper.getLocation(newFeed.getLocations(), LocationType.STATS).getPath())
+                || !FeedHelper.getLocation(oldFeed.getLocations(), LocationType.TMP)
+                    .getPath().equals(FeedHelper.getLocation(newFeed.getLocations(), LocationType.TMP).getPath())) {
             return true;
         }
         LOG.debug(oldFeed.toShortString() + ": Location identical. Ignoring...");
@@ -139,27 +129,16 @@ public final class UpdateHelper {
 
         for (Cluster cluster : affectedProcess.getClusters().getClusters()) {
             if (!FeedHelper
-                    .getCluster(oldFeed, cluster.getName())
-                    .getValidity()
-                    .getStart()
-                    .equals(FeedHelper.getCluster(newFeed, cluster.getName())
-                            .getValidity().getStart())
-                    || !FeedHelper.getLocation(oldFeed, LocationType.DATA,
-                    cluster.getName()).getPath().equals(
-                    FeedHelper.getLocation(newFeed, LocationType.DATA,
-                            cluster.getName()).getPath())
-                    || !FeedHelper.getLocation(oldFeed, LocationType.META,
-                    cluster.getName()).getPath().equals(
-                    FeedHelper.getLocation(newFeed, LocationType.META,
-                            cluster.getName()).getPath())
-                    || !FeedHelper.getLocation(oldFeed, LocationType.STATS,
-                    cluster.getName()).getPath().equals(
-                    FeedHelper.getLocation(newFeed, LocationType.STATS,
-                            cluster.getName()).getPath())
-                    || !FeedHelper.getLocation(oldFeed, LocationType.TMP,
-                    cluster.getName()).getPath().equals(
-                    FeedHelper.getLocation(newFeed, LocationType.TMP,
-                            cluster.getName()).getPath())) {
+                    .getCluster(oldFeed, cluster.getName()).getValidity().getStart()
+                    .equals(FeedHelper.getCluster(newFeed, cluster.getName()).getValidity().getStart())
+                    || !FeedHelper.getLocation(oldFeed, LocationType.DATA, cluster.getName()).getPath()
+                    .equals(FeedHelper.getLocation(newFeed, LocationType.DATA, cluster.getName()).getPath())
+                    || !FeedHelper.getLocation(oldFeed, LocationType.META, cluster.getName()).getPath()
+                    .equals(FeedHelper.getLocation(newFeed, LocationType.META, cluster.getName()).getPath())
+                    || !FeedHelper.getLocation(oldFeed, LocationType.STATS, cluster.getName()).getPath()
+                    .equals(FeedHelper.getLocation(newFeed, LocationType.STATS, cluster.getName()).getPath())
+                    || !FeedHelper.getLocation(oldFeed, LocationType.TMP, cluster.getName()).getPath()
+                    .equals(FeedHelper.getLocation(newFeed, LocationType.TMP, cluster.getName()).getPath())) {
                 return true;
             }
             LOG.debug(oldFeed.toShortString() + ": Feed on cluster" + cluster.getName() + " identical. Ignoring...");

http://git-wip-us.apache.org/repos/asf/incubator-falcon/blob/bdadf2ed/common/src/main/java/org/apache/falcon/util/ApplicationProperties.java
----------------------------------------------------------------------
diff --git a/common/src/main/java/org/apache/falcon/util/ApplicationProperties.java b/common/src/main/java/org/apache/falcon/util/ApplicationProperties.java
index f5dbc83..5d670ef 100644
--- a/common/src/main/java/org/apache/falcon/util/ApplicationProperties.java
+++ b/common/src/main/java/org/apache/falcon/util/ApplicationProperties.java
@@ -30,9 +30,12 @@ import java.util.HashSet;
 import java.util.Properties;
 import java.util.Set;
 
+/**
+ * Base class for reading application properties.
+ */
 public abstract class ApplicationProperties extends Properties {
 
-    private static Logger LOG = Logger.getLogger(ApplicationProperties.class);
+    private static final Logger LOG = Logger.getLogger(ApplicationProperties.class);
 
     protected enum LocationType {
         FILE, HOME, CLASSPATH
@@ -81,12 +84,10 @@ public abstract class ApplicationProperties extends Properties {
         try {
             if (location == LocationType.CLASSPATH) {
                 if (getClass().getResource(propertyFile) != null) {
-                    LOG.info("Property file being loaded from " +
-                            getClass().getResource(propertyFile));
+                    LOG.info("Property file being loaded from " + getClass().getResource(propertyFile));
                     resource = getClass().getResourceAsStream(propertyFile);
                 } else {
-                    LOG.info("Property file being loaded from " +
-                            getClass().getResource("/" + propertyFile));
+                    LOG.info("Property file being loaded from " + getClass().getResource("/" + propertyFile));
                     resource = getClass().getResourceAsStream("/" + propertyFile);
                 }
             } else {