diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 8468afb5bf5..76a042a2e1f 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -123,6 +123,8 @@ Release 2.0.5-beta - UNRELEASED
     MAPREDUCE-5113. Streaming input/output types are ignored with java
     mapper/reducer. (sandyr via tucu)
 
+    MAPREDUCE-5098. Fix findbugs warnings in gridmix. (kkambatl via tucu)
+
 Release 2.0.4-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-tools/hadoop-gridmix/dev-support/findbugs-exclude.xml b/hadoop-tools/hadoop-gridmix/dev-support/findbugs-exclude.xml
new file mode 100644
index 00000000000..92458d4a213
--- /dev/null
+++ b/hadoop-tools/hadoop-gridmix/dev-support/findbugs-exclude.xml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+-->
+<FindBugsFilter>
+
+ <!-- Ignore some irrelevant serialization warnings -->
+  <Match>
+    <Class name="org.apache.hadoop.mapred.gridmix.GridmixRecord$Comparator" />
+    <Bug pattern="SE_COMPARATOR_SHOULD_BE_SERIALIZABLE" />
+  </Match>
+
+  <!-- The called methods actually might throw Exceptions -->
+  <Match>
+    <Class name="org.apache.hadoop.mapred.gridmix.ExecutionSummarizer"/>
+    <Method name="processJobState"/>
+    <Bug pattern="REC_CATCH_EXCEPTION"/>
+    <Bug code="REC"/>
+  </Match>
+</FindBugsFilter>
diff --git a/hadoop-tools/hadoop-gridmix/pom.xml b/hadoop-tools/hadoop-gridmix/pom.xml
index a9774d166bd..61fdd0ecdab 100644
--- a/hadoop-tools/hadoop-gridmix/pom.xml
+++ b/hadoop-tools/hadoop-gridmix/pom.xml
@@ -100,6 +100,16 @@
 
   <build>
     <plugins>
+       <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>findbugs-maven-plugin</artifactId>
+         <configuration>
+          <findbugsXmlOutput>true</findbugsXmlOutput>
+          <xmlOutput>true</xmlOutput>
+          <excludeFilterFile>${basedir}/dev-support/findbugs-exclude.xml</excludeFilterFile>
+          <effort>Max</effort>
+        </configuration>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-antrun-plugin</artifactId>
diff --git a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/JobMonitor.java b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/JobMonitor.java
index 64e0c7a0bea..341c49a9c99 100644
--- a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/JobMonitor.java
+++ b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/JobMonitor.java
@@ -86,9 +86,7 @@ class JobMonitor implements Gridmix.Component<JobStats> {
    * Add a running job's status to the polling queue.
    */
   public void add(JobStats job) throws InterruptedException {
-    synchronized (runningJobs) {
       runningJobs.put(job);
-    }
   }
 
   /**
@@ -147,12 +145,10 @@ class JobMonitor implements Gridmix.Component<JobStats> {
       boolean shutdown;
       while (true) {
         try {
-          synchronized (runningJobs) {
-            synchronized (mJobs) {
-              graceful = JobMonitor.this.graceful;
-              shutdown = JobMonitor.this.shutdown;
-              runningJobs.drainTo(mJobs);
-            }
+          synchronized (mJobs) {
+            graceful = JobMonitor.this.graceful;
+            shutdown = JobMonitor.this.shutdown;
+            runningJobs.drainTo(mJobs);
           }
 
           // shutdown conditions; either shutdown requested and all jobs
@@ -160,11 +156,9 @@ class JobMonitor implements Gridmix.Component<JobStats> {
           // submitted jobs not in the monitored set
           if (shutdown) {
             if (!graceful) {
-              synchronized (runningJobs) {
-                while (!runningJobs.isEmpty()) {
-                  synchronized (mJobs) {
-                    runningJobs.drainTo(mJobs);
-                  }
+              while (!runningJobs.isEmpty()) {
+                synchronized (mJobs) {
+                  runningJobs.drainTo(mJobs);
                 }
               }
               break;
diff --git a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/SleepJob.java b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/SleepJob.java
index a9f2999dd3c..6c2a0480bb8 100644
--- a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/SleepJob.java
+++ b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/SleepJob.java
@@ -84,7 +84,7 @@ public class SleepJob extends GridmixJob {
       String[] hosts) throws IOException {
     super(conf, submissionMillis, jobdesc, outRoot, ugi, seq);
     this.fakeLocations = numLocations;
-    this.hosts = hosts;
+    this.hosts = hosts.clone();
     this.selector = (fakeLocations > 0)? new Selector(hosts.length, (float) fakeLocations
         / hosts.length, rand.get()) : null;
     this.mapTasksOnly = conf.getBoolean(SLEEPJOB_MAPTASK_ONLY, false);
@@ -289,9 +289,9 @@ public class SleepJob extends GridmixJob {
       this.id = id;
       this.sleepDuration = sleepDuration;
       nSpec = reduceDurations.length;
-      this.reduceDurations = reduceDurations;
+      this.reduceDurations = reduceDurations.clone();
       this.nMaps = nMaps;
-      this.locations = locations;
+      this.locations = locations.clone();
     }
 
     @Override
@@ -349,7 +349,7 @@ public class SleepJob extends GridmixJob {
 
     @Override
     public String[] getLocations() {
-      return locations;
+      return locations.clone();
     }
   }
 
diff --git a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/emulators/resourceusage/TotalHeapUsageEmulatorPlugin.java b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/emulators/resourceusage/TotalHeapUsageEmulatorPlugin.java
index b9971dc2af5..4cfe1b533a2 100644
--- a/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/emulators/resourceusage/TotalHeapUsageEmulatorPlugin.java
+++ b/hadoop-tools/hadoop-gridmix/src/main/java/org/apache/hadoop/mapred/gridmix/emulators/resourceusage/TotalHeapUsageEmulatorPlugin.java
@@ -93,7 +93,7 @@ implements ResourceUsageEmulatorPlugin {
   
   private static final float DEFAULT_HEAP_LOAD_RATIO = 0.1F;
   
-  public static int ONE_MB = 1024 * 1024;
+  public static final int ONE_MB = 1024 * 1024;
   
   /**
    * Defines the core heap usage emulation algorithm. This engine is expected
@@ -129,7 +129,8 @@ implements ResourceUsageEmulatorPlugin {
   public static class DefaultHeapUsageEmulator 
   implements HeapUsageEmulatorCore {
     // store the unit loads in a list
-    protected static ArrayList<Object> heapSpace = new ArrayList<Object>();
+    protected static final ArrayList<Object> heapSpace =
+        new ArrayList<Object>();
     
     /**
      * Increase heap usage by current process by the given amount.