diff --git a/heron/metricsmgr/src/java/com/twitter/heron/metricsmgr/MetricsManager.java b/heron/metricsmgr/src/java/com/twitter/heron/metricsmgr/MetricsManager.java
index 907f3d2d661..51fba620b76 100644
--- a/heron/metricsmgr/src/java/com/twitter/heron/metricsmgr/MetricsManager.java
+++ b/heron/metricsmgr/src/java/com/twitter/heron/metricsmgr/MetricsManager.java
@@ -97,6 +97,8 @@ public class MetricsManager {
   private final String topologyName;
   private final String metricsmgrId;
 
+  private final long mainThreadId;
+
   /**
    * Metrics manager constructor
    */
@@ -123,6 +125,8 @@ public MetricsManager(String topologyName, String serverHost,
     this.metricsCollector = new MetricsCollector(metricsManagerServerLoop, metricsQueue);
     this.heronMetricsExportIntervalSec = systemConfig.getHeronMetricsExportIntervalSec();
 
+    this.mainThreadId = Thread.currentThread().getId();
+
     // Set up the internal Metrics Export routine
     setupInternalMetricsExport();
 
@@ -192,8 +196,8 @@ public static void main(String[] args) throws IOException {
     if (args.length != 6) {
       throw new RuntimeException(
           "Invalid arguments; Usage: java com.twitter.heron.metricsmgr.MetricsManager "
-          + "<id> <port> <topname> <topid> <heron_internals_config_filename> "
-          + "<metrics_sinks_config_filename>");
+              + "<id> <port> <topname> <topid> <heron_internals_config_filename> "
+              + "<metrics_sinks_config_filename>");
     }
 
     String metricsmgrId = args[0];
@@ -221,7 +225,7 @@ public static void main(String[] args) throws IOException {
     LoggingHelper.addLoggingHandler(new ErrorReportLoggingHandler());
 
     LOG.info(String.format("Starting Metrics Manager for topology %s with topologyId %s with "
-        + "Metrics Manager Id %s, Merics Manager Port: %d.",
+            + "Metrics Manager Id %s, Merics Manager Port: %d.",
         topologyName, topologyId, metricsmgrId, metricsPort));
 
     LOG.info("System Config: " + systemConfig);
@@ -328,26 +332,46 @@ public class DefaultExceptionHandler implements Thread.UncaughtExceptionHandler
      * Handler for uncaughtException
      */
     public void uncaughtException(Thread thread, Throwable exception) {
-      String threadName = thread.getName();
+      // We would fail fast when errors occur
+      if (exception instanceof Error) {
+        LOG.log(Level.SEVERE,
+            "Error caught in thread: " + thread.getName()
+                + " with thread id: " + thread.getId() + ". Process halting...",
+            exception);
+        Runtime.getRuntime().halt(1);
+      }
+
+      // We would fail fast when exceptions happen in main thread
+      if (thread.getId() == mainThreadId) {
+        LOG.log(Level.SEVERE,
+            "Exception caught in main thread. Process halting...",
+            exception);
+        Runtime.getRuntime().halt(1);
+      }
+
       LOG.log(Level.SEVERE,
-          "Exception caught in thread: " + threadName + " with thread id: " + thread.getId(),
+          "Exception caught in thread: " + thread.getName() + " with thread id: " + thread.getId(),
           exception);
 
-      String sinkId = threadName;
-      Integer thisSinkRetryAttempts = sinksRetryAttempts.remove(sinkId);
-
-      // Remove the old sink executor
-      SinkExecutor oldSinkExecutor = sinkExecutors.remove(sinkId);
+      String sinkId = null;
+      Integer thisSinkRetryAttempts = 0;
 
-      if (oldSinkExecutor != null) {
+      // We enforced the name of thread running particular IMetricsSink equal to its sink-id
+      // If the thread name is a key of SinkExecutors, then it is a thread running IMetricsSink
+      if (sinkExecutors.containsKey(thread.getName())) {
+        sinkId = thread.getName();
+        // Remove the old sink executor
+        SinkExecutor oldSinkExecutor = sinkExecutors.remove(sinkId);
         // Remove the unneeded Communicator bind with Metrics Manager Server
         metricsManagerServer.removeSinkCommunicator(oldSinkExecutor.getCommunicator());
-      }
 
-      // Close the sink
-      SysUtils.closeIgnoringExceptions(oldSinkExecutor);
+        // Close the sink
+        SysUtils.closeIgnoringExceptions(oldSinkExecutor);
 
-      if (oldSinkExecutor != null && thisSinkRetryAttempts != 0) {
+        thisSinkRetryAttempts = sinksRetryAttempts.remove(sinkId);
+      }
+
+      if (sinkId != null && thisSinkRetryAttempts != 0) {
         LOG.info(String.format("Restarting IMetricsSink: %s with %d available retries",
             sinkId, thisSinkRetryAttempts));
 
@@ -363,24 +387,23 @@ public void uncaughtException(Thread thread, Throwable exception) {
         }
         sinksRetryAttempts.put(sinkId, thisSinkRetryAttempts);
 
-
         // Update the list of Communicator in Metrics Manager Server
         metricsManagerServer.addSinkCommunicator(newSinkExecutor.getCommunicator());
 
         // Restart it
         executors.execute(newSinkExecutor);
-      } else if (oldSinkExecutor != null
+      } else if (sinkId != null
           && thisSinkRetryAttempts == 0
           && sinkExecutors.size() > 0) {
         // If the dead executor is the only one executor and it is removed,
         // e.g. sinkExecutors.size() == 0, we would exit the process directly
 
-        LOG.severe("Could not recover from exceptions for IMetricsSink: " + sinkId);
+        LOG.severe("Failed to recover from exceptions for IMetricsSink: " + sinkId);
         LOG.info(sinkId + " would close and keep running rest sinks: " + sinkExecutors.keySet());
       } else {
-        // We met metrics manager itself exceptions or we have retried too many times
+        // It is not recoverable (retried too many times, or not an exception from IMetricsSink)
         // So we would do basic cleaning and exit
-        LOG.info("Could not recover from exceptions; Metrics Manager Exiting");
+        LOG.info("Failed to recover from exceptions; Metrics Manager Exiting");
         for (Handler handler : java.util.logging.Logger.getLogger("").getHandlers()) {
           handler.close();
         }
@@ -388,7 +411,6 @@ public void uncaughtException(Thread thread, Throwable exception) {
         // thread in the pool. Threads may implement a clean Interrupt logic.
         executors.shutdownNow();
 
-        // TODO : It is not clear if this signal should be sent to all the threads
         // (including threads not owned by HeronInstance). To be safe, not sending these
         // interrupts.
         Runtime.getRuntime().halt(1);