diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 08a6d248b82..6e1c79386e4 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -83,6 +83,9 @@ Release 2.5.0 - UNRELEASED
     MAPREDUCE-5888. Failed job leaves hung AM after it unregisters (Jason Lowe
     via jeagles)
 
+    MAPREDUCE-5814. fat jar with *-default.xml may fail when
+    mapreduce.job.classloader=true. (Gera Shegalov via jlowe)
+
 Release 2.4.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRApps.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRApps.java
index e3294d70fae..d72a1bff269 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRApps.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRApps.java
@@ -33,6 +33,7 @@ import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import com.google.common.annotations.VisibleForTesting;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience.Private;
@@ -344,8 +345,7 @@ public class MRApps extends Apps {
         if (LOG.isDebugEnabled()) {
           LOG.debug("APP_CLASSPATH=" + appClasspath);
         }
-        String[] systemClasses = conf.getStrings(
-            MRJobConfig.MAPREDUCE_JOB_CLASSLOADER_SYSTEM_CLASSES);
+        String[] systemClasses = getSystemClasses(conf);
         ClassLoader jobClassLoader = createJobClassLoader(appClasspath,
             systemClasses);
         if (jobClassLoader != null) {
@@ -356,6 +356,12 @@ public class MRApps extends Apps {
     }
   }
 
+  @VisibleForTesting
+  static String[] getSystemClasses(Configuration conf) {
+    return conf.getTrimmedStrings(
+        MRJobConfig.MAPREDUCE_JOB_CLASSLOADER_SYSTEM_CLASSES);
+  }
+
   private static ClassLoader createJobClassLoader(final String appClasspath,
       final String[] systemClasses) throws IOException {
     try {
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/util/TestMRApps.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/util/TestMRApps.java
index fd59b8170d4..36a6a2a9c6f 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/util/TestMRApps.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/util/TestMRApps.java
@@ -33,6 +33,7 @@ import java.io.IOException;
 import java.net.URI;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.hadoop.conf.Configuration;
@@ -58,6 +59,7 @@ import org.apache.hadoop.yarn.api.records.LocalResource;
 import org.apache.hadoop.yarn.api.records.LocalResourceType;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
+import org.apache.hadoop.yarn.util.ApplicationClassLoader;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -488,4 +490,36 @@ public class TestMRApps {
     assertTrue(MRApps.TaskStateUI.COMPLETED.correspondsTo(TaskState.KILLED));
     assertTrue(MRApps.TaskStateUI.RUNNING.correspondsTo(TaskState.RUNNING));
   }
+
+
+  private static final String[] SYS_CLASSES = new String[] {
+      "/java/fake/Klass",
+      "/javax/fake/Klass",
+      "/org/apache/commons/logging/fake/Klass",
+      "/org/apache/log4j/fake/Klass",
+      "/org/apache/hadoop/fake/Klass"
+  };
+
+  private static final String[] DEFAULT_XMLS = new String[] {
+        "core-default.xml",
+      "mapred-default.xml",
+        "hdfs-default.xml",
+        "yarn-default.xml"
+  };
+
+  @Test
+  public void testSystemClasses() {
+    final List<String> systemClasses =
+        Arrays.asList(MRApps.getSystemClasses(new Configuration()));
+    for (String defaultXml : DEFAULT_XMLS) {
+      assertTrue(defaultXml + " must be system resource",
+          ApplicationClassLoader.isSystemClass(defaultXml, systemClasses));
+    }
+    for (String klass : SYS_CLASSES) {
+      assertTrue(klass + " must be system class",
+          ApplicationClassLoader.isSystemClass(klass, systemClasses));
+    }
+    assertFalse("/fake/Klass must not be a system class",
+        ApplicationClassLoader.isSystemClass("/fake/Klass", systemClasses));
+  }
 }
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
index fa6741953bd..1a25554b45d 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
@@ -1648,7 +1648,9 @@
 
 <property>
    <name>mapreduce.job.classloader.system.classes</name>
-   <value>java.,javax.,org.apache.commons.logging.,org.apache.log4j.,org.apache.hadoop.</value>
+   <value>java.,javax.,org.apache.commons.logging.,org.apache.log4j.,
+          org.apache.hadoop.,core-default.xml,hdfs-default.xml,
+          mapred-default.xml,yarn-default.xml</value>
   <description>A comma-separated list of classes that should be loaded from the
     system classpath, not the user-supplied JARs, when mapreduce.job.classloader
     is enabled. Names ending in '.' (period) are treated as package names,
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/ApplicationClassLoader.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/ApplicationClassLoader.java
index 6dcea6ca05c..63dc5b798c1 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/ApplicationClassLoader.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/ApplicationClassLoader.java
@@ -173,7 +173,7 @@ public class ApplicationClassLoader extends URLClassLoader {
   }
 
   @VisibleForTesting
-  static boolean isSystemClass(String name, List<String> systemClasses) {
+  public static boolean isSystemClass(String name, List<String> systemClasses) {
     if (systemClasses != null) {
       String canonicalName = name.replace('/', '.');
       while (canonicalName.startsWith(".")) {