Unnecessary log removal (#2208)

Remove unnecessary logs to clean up code in Helix.
diff --git a/helix-core/src/main/java/org/apache/helix/manager/zk/CallbackEventThreadPoolFactory.java b/helix-core/src/main/java/org/apache/helix/manager/zk/CallbackEventThreadPoolFactory.java
index 73cbf85..1a79f88 100644
--- a/helix-core/src/main/java/org/apache/helix/manager/zk/CallbackEventThreadPoolFactory.java
+++ b/helix-core/src/main/java/org/apache/helix/manager/zk/CallbackEventThreadPoolFactory.java
@@ -82,10 +82,6 @@
         result.allowCoreThreadTimeOut(true);
         _managerToCallBackThreadPoolMap.put(hash, result);
         _callBackEventProcessorCountPerThreadPool.put(hash, new AtomicInteger(1));
-      } catch (Exception e) {
-        logger.error(String
-            .format("Error when creating new ThreadPoolExecutor for %s.", hash), e);
-        throw e;
       } finally {
         _lock.writeLock().unlock();
       }
diff --git a/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java b/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
index 1ed87fe..65303b3 100644
--- a/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
+++ b/helix-core/src/main/java/org/apache/helix/manager/zk/ZKHelixManager.java
@@ -781,9 +781,6 @@
          */
         handleNewSession(ZKUtil.toHexSessionId(sessionId));
         break;
-      } catch (HelixException e) {
-        LOG.error("fail to createClient.", e);
-        throw e;
       } catch (Exception e) {
         retryCount++;
         LOG.error("fail to createClient. retry " + retryCount, e);
diff --git a/helix-core/src/main/java/org/apache/helix/manager/zk/ZkBaseDataAccessor.java b/helix-core/src/main/java/org/apache/helix/manager/zk/ZkBaseDataAccessor.java
index 0c7a94f..e95fe34 100644
--- a/helix-core/src/main/java/org/apache/helix/manager/zk/ZkBaseDataAccessor.java
+++ b/helix-core/src/main/java/org/apache/helix/manager/zk/ZkBaseDataAccessor.java
@@ -393,9 +393,6 @@
           result._retCode = RetCode.ERROR;
           return result;
         }
-      } catch (ZkBadVersionException e) {
-        LOG.debug("Exception while setting path: " + path, e);
-        throw e;
       } catch (Exception e) {
         LOG.error("Exception while setting path: " + path, e);
         result._retCode = RetCode.ERROR;
diff --git a/helix-core/src/main/java/org/apache/helix/tools/commandtools/JmxDumper.java b/helix-core/src/main/java/org/apache/helix/tools/commandtools/JmxDumper.java
index d7d59dd..824c7b6 100644
--- a/helix-core/src/main/java/org/apache/helix/tools/commandtools/JmxDumper.java
+++ b/helix-core/src/main/java/org/apache/helix/tools/commandtools/JmxDumper.java
@@ -197,7 +197,6 @@
   }
 
   void init() throws Exception {
-    try {
       Set<ObjectInstance> existingInstances =
           _mbeanServer.queryMBeans(new ObjectName(_namePattern), null);
       _logger.info("Total " + existingInstances.size() + " mbeans matched " + _namePattern);
@@ -210,10 +209,6 @@
       FileWriter fos = new FileWriter(_outputFileName);
       System.out.println(_outputFileName);
       _outputFile = new PrintWriter(fos);
-    } catch (Exception e) {
-      _logger.error("fail to get all existing mbeans in " + _domain, e);
-      throw e;
-    }
   }
 
   @Override
diff --git a/helix-core/src/main/java/org/apache/helix/tools/commandtools/TaskAdmin.java b/helix-core/src/main/java/org/apache/helix/tools/commandtools/TaskAdmin.java
index f565e0f..52a2524 100644
--- a/helix-core/src/main/java/org/apache/helix/tools/commandtools/TaskAdmin.java
+++ b/helix-core/src/main/java/org/apache/helix/tools/commandtools/TaskAdmin.java
@@ -92,9 +92,8 @@
             zkAddr);
     helixMgr.connect();
     TaskDriver driver = new TaskDriver(helixMgr);
-    try {
-      TaskDriver.DriverCommand cmd = TaskDriver.DriverCommand.valueOf(args[0]);
-      switch (cmd) {
+    TaskDriver.DriverCommand cmd = TaskDriver.DriverCommand.valueOf(args[0]);
+    switch (cmd) {
       case start:
         if (cl.hasOption(WORKFLOW_FILE_OPTION)) {
           driver.start(Workflow.parse(new File(cl.getOptionValue(WORKFLOW_FILE_OPTION))));
@@ -123,11 +122,6 @@
       default:
         throw new IllegalArgumentException("Unknown command " + args[0]);
       }
-    } catch (IllegalArgumentException e) {
-      LOG.error("Unknown driver command " + args[0]);
-      throw e;
-    }
-
     helixMgr.disconnect();
   }
 
diff --git a/helix-rest/src/main/java/org/apache/helix/rest/client/CustomRestClientImpl.java b/helix-rest/src/main/java/org/apache/helix/rest/client/CustomRestClientImpl.java
index 6406f0b..b358b6c 100644
--- a/helix-rest/src/main/java/org/apache/helix/rest/client/CustomRestClientImpl.java
+++ b/helix-rest/src/main/java/org/apache/helix/rest/client/CustomRestClientImpl.java
@@ -143,8 +143,6 @@
 
       return response;
     } catch (IOException e) {
-      LOG.error("Failed to perform customized health check. Is participant endpoint {} available?",
-          url, e);
       // Release connection to be reused and avoid connection leakage.
       postRequest.releaseConnection();
       throw e;
diff --git a/helix-rest/src/main/java/org/apache/helix/rest/server/HelixRestServer.java b/helix-rest/src/main/java/org/apache/helix/rest/server/HelixRestServer.java
index f8e78ee..66413f8 100644
--- a/helix-rest/src/main/java/org/apache/helix/rest/server/HelixRestServer.java
+++ b/helix-rest/src/main/java/org/apache/helix/rest/server/HelixRestServer.java
@@ -150,7 +150,6 @@
         }
       }
     } catch (Exception e) {
-      LOG.error("Failed to initialize helix rest server. Tearing down.");
       cleanupResourceConfigs();
       throw e;
     }
diff --git a/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/InstancesAccessor.java b/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/InstancesAccessor.java
index 076fe6d..22e0314 100644
--- a/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/InstancesAccessor.java
+++ b/helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/InstancesAccessor.java
@@ -274,7 +274,7 @@
       return JSONRepresentation(result);
     } catch (HelixException e) {
       _logger
-          .error(String.format("Current cluster %s has issue with health checks!", clusterId), e);
+              .error(String.format("Current cluster %s has issue with health checks!", clusterId), e);
       throw new HelixHealthException(e);
     } catch (Exception e) {
       _logger.error(String.format(
diff --git a/helix-view-aggregator/src/main/java/org/apache/helix/view/statemodel/DistViewAggregatorStateModel.java b/helix-view-aggregator/src/main/java/org/apache/helix/view/statemodel/DistViewAggregatorStateModel.java
index 7ac20b0..e335e05 100644
--- a/helix-view-aggregator/src/main/java/org/apache/helix/view/statemodel/DistViewAggregatorStateModel.java
+++ b/helix-view-aggregator/src/main/java/org/apache/helix/view/statemodel/DistViewAggregatorStateModel.java
@@ -58,7 +58,7 @@
       _aggregator.start();
     } catch (Exception e) {
       logger.error("Aggregator failed to become leader from stand by for view cluster {}",
-          viewClusterName, e);
+              viewClusterName, e);
       reset();
       throw e;
     }
diff --git a/zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java b/zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
index a24a098..527e46f 100644
--- a/zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
+++ b/zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
@@ -2066,7 +2066,7 @@
         success = true;
       } catch (ZkNoNodeException e) {
         success = false;
-        LOG.debug("zkclient {}, Failed to delete path {}, znode does not exist!", _uid, path);
+        LOG.debug("zkclient {}, Failed to delete path {}, znode does not exist!", _uid, path, e);
       }
       record(path, null, startT, ZkClientMonitor.AccessType.WRITE);
     } catch (Exception e) {