HADOOP-10893. isolated classloader on the client side. Contributed by Sangjin Lee

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1619605 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -8,6 +8,9 @@ Release 2.6.0 - UNRELEASED
 
     HADOOP-10433. Key Management Server based on KeyProvider API. (tucu)
 
+    HADOOP-10893. isolated classloader on the client side (Sangjin Lee via
+    jlowe)
+
   IMPROVEMENTS
 
     HADOOP-10808. Remove unused native code for munlock. (cnauroth)

hadoop-common-project/hadoop-common/dev-support/findbugsExcludeFile.xml

@@ -111,6 +111,11 @@
        <Method name="driver" />
        <Bug pattern="DM_EXIT" />
      </Match>
+     <Match>
+       <Class name="org.apache.hadoop.util.RunJar" />
+       <Method name="run" />
+       <Bug pattern="DM_EXIT" />
+     </Match>
      <!--
        We need to cast objects between old and new api objects
      -->

hadoop-common-project/hadoop-common/src/main/bin/hadoop-config.cmd

@@ -282,10 +282,12 @@ if not "%HADOOP_MAPRED_HOME%\%MAPRED_DIR%" == "%HADOOP_YARN_HOME%\%YARN_DIR%" (
 @rem
 
 if defined HADOOP_CLASSPATH (
-  if defined HADOOP_USER_CLASSPATH_FIRST (
+  if not defined HADOOP_USE_CLIENT_CLASSLOADER (
-    set CLASSPATH=%HADOOP_CLASSPATH%;%CLASSPATH%;
+    if defined HADOOP_USER_CLASSPATH_FIRST (
-  ) else (
+      set CLASSPATH=%HADOOP_CLASSPATH%;%CLASSPATH%;
-    set CLASSPATH=%CLASSPATH%;%HADOOP_CLASSPATH%;
+    ) else (
+      set CLASSPATH=%CLASSPATH%;%HADOOP_CLASSPATH%;
+    )
   )
 )
 

hadoop-common-project/hadoop-common/src/main/bin/hadoop-config.sh

@@ -29,6 +29,23 @@
 #                                    by doing 
 #                                    export HADOOP_USER_CLASSPATH_FIRST=true
 #
+#   HADOOP_USE_CLIENT_CLASSLOADER    When defined, HADOOP_CLASSPATH and the jar
+#                                    as the hadoop jar argument are handled by
+#                                    by a separate isolated client classloader.
+#                                    If it is set, HADOOP_USER_CLASSPATH_FIRST
+#                                    is ignored. Can be defined by doing
+#                                    export HADOOP_USE_CLIENT_CLASSLOADER=true
+#
+#   HADOOP_CLIENT_CLASSLOADER_SYSTEM_CLASSES
+#                                    When defined, it overrides the default
+#                                    definition of system classes for the client
+#                                    classloader when
+#                                    HADOOP_USE_CLIENT_CLASSLOADER is enabled.
+#                                    Names ending in '.' (period) are treated as
+#                                    package names, and names starting with a
+#                                    '-' are treated as negative matches.
+#                                    For example,
+#                                    export HADOOP_CLIENT_CLASSLOADER_SYSTEM_CLASSES="-org.apache.hadoop.UserClass,java.,javax.,org.apache.hadoop."
 
 this="${BASH_SOURCE-$0}"
 common_bin=$(cd -P -- "$(dirname -- "$this")" && pwd -P)
@@ -282,7 +299,9 @@ fi
 # Add the user-specified CLASSPATH via HADOOP_CLASSPATH
 # Add it first or last depending on if user has
 # set env-var HADOOP_USER_CLASSPATH_FIRST
-if [ "$HADOOP_CLASSPATH" != "" ]; then
+# if the user set HADOOP_USE_CLIENT_CLASSLOADER, HADOOP_CLASSPATH is not added
+# to the classpath
+if [[ ( "$HADOOP_CLASSPATH" != "" ) && ( "$HADOOP_USE_CLIENT_CLASSLOADER" = "" ) ]]; then
   # Prefix it if its to be preceded
   if [ "$HADOOP_USER_CLASSPATH_FIRST" != "" ]; then
     CLASSPATH=${HADOOP_CLASSPATH}:${CLASSPATH}

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/ApplicationClassLoader.java

@@ -0,0 +1,219 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.util;
+
+import java.io.File;
+import java.io.FilenameFilter;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience.Public;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
+
+/**
+ * A {@link URLClassLoader} for application isolation. Classes from the
+ * application JARs are loaded in preference to the parent loader.
+ */
+@Public
+@Unstable
+public class ApplicationClassLoader extends URLClassLoader {
+  /**
+   * Default value of the system classes if the user did not override them.
+   * JDK classes, hadoop classes and resources, and some select third-party
+   * classes are considered system classes, and are not loaded by the
+   * application classloader.
+   */
+  public static final String DEFAULT_SYSTEM_CLASSES =
+        "java.," +
+        "javax.," +
+        "org.w3c.dom.," +
+        "org.xml.sax.," +
+        "org.apache.commons.logging.," +
+        "org.apache.log4j.," +
+        "org.apache.hadoop.," +
+        "core-default.xml," +
+        "hdfs-default.xml," +
+        "mapred-default.xml," +
+        "yarn-default.xml";
+
+  private static final Log LOG =
+    LogFactory.getLog(ApplicationClassLoader.class.getName());
+
+  private static final FilenameFilter JAR_FILENAME_FILTER =
+    new FilenameFilter() {
+      @Override
+      public boolean accept(File dir, String name) {
+        return name.endsWith(".jar") || name.endsWith(".JAR");
+      }
+  };
+
+  private final ClassLoader parent;
+  private final List<String> systemClasses;
+
+  public ApplicationClassLoader(URL[] urls, ClassLoader parent,
+      List<String> systemClasses) {
+    super(urls, parent);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("urls: " + Arrays.toString(urls));
+      LOG.debug("system classes: " + systemClasses);
+    }
+    this.parent = parent;
+    if (parent == null) {
+      throw new IllegalArgumentException("No parent classloader!");
+    }
+    // if the caller-specified system classes are null or empty, use the default
+    this.systemClasses = (systemClasses == null || systemClasses.isEmpty()) ?
+        Arrays.asList(StringUtils.getTrimmedStrings(DEFAULT_SYSTEM_CLASSES)) :
+        systemClasses;
+    LOG.info("system classes: " + this.systemClasses);
+  }
+
+  public ApplicationClassLoader(String classpath, ClassLoader parent,
+      List<String> systemClasses) throws MalformedURLException {
+    this(constructUrlsFromClasspath(classpath), parent, systemClasses);
+  }
+
+  static URL[] constructUrlsFromClasspath(String classpath)
+      throws MalformedURLException {
+    List<URL> urls = new ArrayList<URL>();
+    for (String element : classpath.split(File.pathSeparator)) {
+      if (element.endsWith("/*")) {
+        String dir = element.substring(0, element.length() - 1);
+        File[] files = new File(dir).listFiles(JAR_FILENAME_FILTER);
+        if (files != null) {
+          for (File file : files) {
+            urls.add(file.toURI().toURL());
+          }
+        }
+      } else {
+        File file = new File(element);
+        if (file.exists()) {
+          urls.add(new File(element).toURI().toURL());
+        }
+      }
+    }
+    return urls.toArray(new URL[urls.size()]);
+  }
+
+  @Override
+  public URL getResource(String name) {
+    URL url = null;
+    
+    if (!isSystemClass(name, systemClasses)) {
+      url= findResource(name);
+      if (url == null && name.startsWith("/")) {
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("Remove leading / off " + name);
+        }
+        url= findResource(name.substring(1));
+      }
+    }
+
+    if (url == null) {
+      url= parent.getResource(name);
+    }
+
+    if (url != null) {
+      if (LOG.isDebugEnabled()) {
+        LOG.debug("getResource("+name+")=" + url);
+      }
+    }
+    
+    return url;
+  }
+
+  @Override
+  public Class<?> loadClass(String name) throws ClassNotFoundException {
+    return this.loadClass(name, false);
+  }
+
+  @Override
+  protected synchronized Class<?> loadClass(String name, boolean resolve)
+      throws ClassNotFoundException {
+    
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Loading class: " + name);
+    }
+
+    Class<?> c = findLoadedClass(name);
+    ClassNotFoundException ex = null;
+
+    if (c == null && !isSystemClass(name, systemClasses)) {
+      // Try to load class from this classloader's URLs. Note that this is like
+      // the servlet spec, not the usual Java 2 behaviour where we ask the
+      // parent to attempt to load first.
+      try {
+        c = findClass(name);
+        if (LOG.isDebugEnabled() && c != null) {
+          LOG.debug("Loaded class: " + name + " ");
+        }
+      } catch (ClassNotFoundException e) {
+        if (LOG.isDebugEnabled()) {
+          LOG.debug(e);
+        }
+        ex = e;
+      }
+    }
+
+    if (c == null) { // try parent
+      c = parent.loadClass(name);
+      if (LOG.isDebugEnabled() && c != null) {
+        LOG.debug("Loaded class from parent: " + name + " ");
+      }
+    }
+
+    if (c == null) {
+      throw ex != null ? ex : new ClassNotFoundException(name);
+    }
+
+    if (resolve) {
+      resolveClass(c);
+    }
+
+    return c;
+  }
+
+  public static boolean isSystemClass(String name, List<String> systemClasses) {
+    if (systemClasses != null) {
+      String canonicalName = name.replace('/', '.');
+      while (canonicalName.startsWith(".")) {
+        canonicalName=canonicalName.substring(1);
+      }
+      for (String c : systemClasses) {
+        boolean result = true;
+        if (c.startsWith("-")) {
+          c = c.substring(1);
+          result = false;
+        }
+        if (c.endsWith(".") && canonicalName.startsWith(c)) {
+          return result;
+        } else if (canonicalName.equals(c)) {
+          return result;
+        }
+      }
+    }
+    return false;
+  }
+}

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/RunJar.java

@@ -18,23 +18,25 @@
 
 package org.apache.hadoop.util;
 
-import java.lang.reflect.Array;
+import java.io.File;
-import java.lang.reflect.Method;
-import java.lang.reflect.InvocationTargetException;
-import java.net.URL;
-import java.net.URLClassLoader;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.io.File;
+import java.lang.reflect.Array;
-import java.util.regex.Pattern;
+import java.lang.reflect.InvocationTargetException;
-import java.util.Arrays;
+import java.lang.reflect.Method;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Enumeration;
-import java.util.jar.JarFile;
+import java.util.List;
 import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
 import java.util.jar.Manifest;
+import java.util.regex.Pattern;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
@@ -55,6 +57,21 @@ public class RunJar {
    */
   public static final int SHUTDOWN_HOOK_PRIORITY = 10;
 
+  /**
+   * Environment key for using the client classloader.
+   */
+  public static final String HADOOP_USE_CLIENT_CLASSLOADER =
+      "HADOOP_USE_CLIENT_CLASSLOADER";
+  /**
+   * Environment key for the (user-provided) hadoop classpath.
+   */
+  public static final String HADOOP_CLASSPATH = "HADOOP_CLASSPATH";
+  /**
+   * Environment key for the system classes.
+   */
+  public static final String HADOOP_CLIENT_CLASSLOADER_SYSTEM_CLASSES =
+      "HADOOP_CLIENT_CLASSLOADER_SYSTEM_CLASSES";
+
   /**
    * Unpack a jar file into a directory.
    *
@@ -116,6 +133,10 @@ private static void ensureDirectory(File dir) throws IOException {
   /** Run a Hadoop job jar.  If the main class is not in the jar's manifest,
    * then it must be provided on the command line. */
   public static void main(String[] args) throws Throwable {
+    new RunJar().run(args);
+  }
+
+  public void run(String[] args) throws Throwable {
     String usage = "RunJar jarFile [mainClass] args...";
 
     if (args.length < 1) {
@@ -187,19 +208,7 @@ public void run() {
 
     unJar(file, workDir);
 
-    ArrayList<URL> classPath = new ArrayList<URL>();
+    ClassLoader loader = createClassLoader(file, workDir);
-    classPath.add(new File(workDir+"/").toURI().toURL());
-    classPath.add(file.toURI().toURL());
-    classPath.add(new File(workDir, "classes/").toURI().toURL());
-    File[] libs = new File(workDir, "lib").listFiles();
-    if (libs != null) {
-      for (int i = 0; i < libs.length; i++) {
-        classPath.add(libs[i].toURI().toURL());
-      }
-    }
-    
-    ClassLoader loader =
-      new URLClassLoader(classPath.toArray(new URL[0]));
 
     Thread.currentThread().setContextClassLoader(loader);
     Class<?> mainClass = Class.forName(mainClassName, true, loader);
@@ -214,5 +223,65 @@ public void run() {
       throw e.getTargetException();
     }
   }
-  
+
+  /**
+   * Creates a classloader based on the environment that was specified by the
+   * user. If HADOOP_USE_CLIENT_CLASSLOADER is specified, it creates an
+   * application classloader that provides the isolation of the user class space
+   * from the hadoop classes and their dependencies. It forms a class space for
+   * the user jar as well as the HADOOP_CLASSPATH. Otherwise, it creates a
+   * classloader that simply adds the user jar to the classpath.
+   */
+  private ClassLoader createClassLoader(File file, final File workDir)
+      throws MalformedURLException {
+    ClassLoader loader;
+    // see if the client classloader is enabled
+    if (useClientClassLoader()) {
+      StringBuilder sb = new StringBuilder();
+      sb.append(workDir+"/").
+          append(File.pathSeparator).append(file).
+          append(File.pathSeparator).append(workDir+"/classes/").
+          append(File.pathSeparator).append(workDir+"/lib/*");
+      // HADOOP_CLASSPATH is added to the client classpath
+      String hadoopClasspath = getHadoopClasspath();
+      if (hadoopClasspath != null && !hadoopClasspath.isEmpty()) {
+        sb.append(File.pathSeparator).append(hadoopClasspath);
+      }
+      String clientClasspath = sb.toString();
+      // get the system classes
+      String systemClasses = getSystemClasses();
+      List<String> systemClassesList = systemClasses == null ?
+          null :
+          Arrays.asList(StringUtils.getTrimmedStrings(systemClasses));
+      // create an application classloader that isolates the user classes
+      loader = new ApplicationClassLoader(clientClasspath,
+          getClass().getClassLoader(), systemClassesList);
+    } else {
+      List<URL> classPath = new ArrayList<URL>();
+      classPath.add(new File(workDir+"/").toURI().toURL());
+      classPath.add(file.toURI().toURL());
+      classPath.add(new File(workDir, "classes/").toURI().toURL());
+      File[] libs = new File(workDir, "lib").listFiles();
+      if (libs != null) {
+        for (int i = 0; i < libs.length; i++) {
+          classPath.add(libs[i].toURI().toURL());
+        }
+      }
+      // create a normal parent-delegating classloader
+      loader = new URLClassLoader(classPath.toArray(new URL[0]));
+    }
+    return loader;
+  }
+
+  boolean useClientClassLoader() {
+    return Boolean.parseBoolean(System.getenv(HADOOP_USE_CLIENT_CLASSLOADER));
+  }
+
+  String getHadoopClasspath() {
+    return System.getenv(HADOOP_CLASSPATH);
+  }
+
+  String getSystemClasses() {
+    return System.getenv(HADOOP_CLIENT_CLASSLOADER_SYSTEM_CLASSES);
+  }
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/ClassLoaderCheck.java

@@ -0,0 +1,33 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.util;
+
+public class ClassLoaderCheck {
+  /**
+   * Verifies the class is loaded by the right classloader.
+   */
+  public static void checkClassLoader(Class cls,
+      boolean shouldBeLoadedByAppClassLoader) {
+    boolean loadedByAppClassLoader =
+        cls.getClassLoader() instanceof ApplicationClassLoader;
+    if ((shouldBeLoadedByAppClassLoader && !loadedByAppClassLoader) ||
+        (!shouldBeLoadedByAppClassLoader && loadedByAppClassLoader)) {
+      throw new RuntimeException("incorrect classloader used");
+    }
+  }
+}

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/ClassLoaderCheckMain.java

@@ -0,0 +1,34 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.util;
+
+/**
+ * Test class used by {@link TestRunJar} to verify that it is loaded by the
+ * {@link ApplicationClassLoader}.
+ */
+public class ClassLoaderCheckMain {
+  public static void main(String[] args) {
+    // ClassLoaderCheckMain should be loaded by the application classloader
+    ClassLoaderCheck.checkClassLoader(ClassLoaderCheckMain.class, true);
+    // ClassLoaderCheckSecond should NOT be loaded by the application
+    // classloader
+    ClassLoaderCheck.checkClassLoader(ClassLoaderCheckSecond.class, false);
+    // ClassLoaderCheckThird should be loaded by the application classloader
+    ClassLoaderCheck.checkClassLoader(ClassLoaderCheckThird.class, true);
+  }
+}

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/ClassLoaderCheckSecond.java

@@ -0,0 +1,24 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.util;
+
+/**
+ * A class {@link ClassLoaderCheckMain} depends on that should be loaded by the
+ * system classloader.
+ */
+public class ClassLoaderCheckSecond {}

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/ClassLoaderCheckThird.java

@@ -0,0 +1,24 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.util;
+
+/**
+ * A class {@link ClassLoaderCheckMain} depends on that should be loaded by the
+ * application classloader.
+ */
+public class ClassLoaderCheckThird {}

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestApplicationClassLoader.java

@@ -16,18 +16,15 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.util;
+package org.apache.hadoop.util;
 
+import static org.apache.hadoop.util.ApplicationClassLoader.constructUrlsFromClasspath;
+import static org.apache.hadoop.util.ApplicationClassLoader.isSystemClass;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
-import static org.apache.hadoop.yarn.util.ApplicationClassLoader.constructUrlsFromClasspath;
-import static org.apache.hadoop.yarn.util.ApplicationClassLoader.isSystemClass;
-
-import com.google.common.base.Splitter;
-import com.google.common.collect.Lists;
 
 import java.io.File;
 import java.io.FileOutputStream;
@@ -43,6 +40,9 @@
 import org.junit.Before;
 import org.junit.Test;
 
+import com.google.common.base.Splitter;
+import com.google.common.collect.Lists;
+
 public class TestApplicationClassLoader {
   
   private static File testDir = new File(System.getProperty("test.build.data",

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestRunJar.java

@@ -17,23 +17,30 @@
  */
 package org.apache.hadoop.util;
 
-import junit.framework.TestCase;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.jar.JarOutputStream;
 import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
 
+import junit.framework.TestCase;
+
+import org.apache.hadoop.fs.FileUtil;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.apache.hadoop.fs.FileUtil;
 
 public class TestRunJar extends TestCase {
   private File TEST_ROOT_DIR;
 
   private static final String TEST_JAR_NAME="test-runjar.jar";
+  private static final String TEST_JAR_2_NAME = "test-runjar2.jar";
 
   @Override
   @Before
@@ -107,4 +114,59 @@ public void testUnJarWithPattern() throws Exception {
                new File(unjarDir, "foobaz.txt").exists());
 
   }
+
+  /**
+   * Tests the client classloader to verify the main class and its dependent
+   * class are loaded correctly by the application classloader, and others are
+   * loaded by the system classloader.
+   */
+  @Test
+  public void testClientClassLoader() throws Throwable {
+    RunJar runJar = spy(new RunJar());
+    // enable the client classloader
+    when(runJar.useClientClassLoader()).thenReturn(true);
+    // set the system classes and blacklist the test main class and the test
+    // third class so they can be loaded by the application classloader
+    String mainCls = ClassLoaderCheckMain.class.getName();
+    String thirdCls = ClassLoaderCheckThird.class.getName();
+    String systemClasses = "-" + mainCls + "," +
+        "-" + thirdCls + "," +
+        ApplicationClassLoader.DEFAULT_SYSTEM_CLASSES;
+    when(runJar.getSystemClasses()).thenReturn(systemClasses);
+
+    // create the test jar
+    File testJar = makeClassLoaderTestJar(mainCls, thirdCls);
+    // form the args
+    String[] args = new String[3];
+    args[0] = testJar.getAbsolutePath();
+    args[1] = mainCls;
+
+    // run RunJar
+    runJar.run(args);
+    // it should not throw an exception
+  }
+
+  private File makeClassLoaderTestJar(String... clsNames) throws IOException {
+    File jarFile = new File(TEST_ROOT_DIR, TEST_JAR_2_NAME);
+    JarOutputStream jstream =
+        new JarOutputStream(new FileOutputStream(jarFile));
+    for (String clsName: clsNames) {
+      String name = clsName.replace('.', '/') + ".class";
+      InputStream entryInputStream = this.getClass().getResourceAsStream(
+          "/" + name);
+      ZipEntry entry = new ZipEntry(name);
+      jstream.putNextEntry(entry);
+      BufferedInputStream bufInputStream = new BufferedInputStream(
+          entryInputStream, 2048);
+      int count;
+      byte[] data = new byte[2048];
+      while ((count = bufInputStream.read(data, 0, 2048)) != -1) {
+        jstream.write(data, 0, count);
+      }
+      jstream.closeEntry();
+    }
+    jstream.close();
+
+    return jarFile;
+  }
 }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/util/MRApps.java

@@ -34,6 +34,7 @@
 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;
@@ -56,6 +57,7 @@
 import org.apache.hadoop.mapreduce.v2.api.records.TaskId;
 import org.apache.hadoop.mapreduce.v2.api.records.TaskState;
 import org.apache.hadoop.mapreduce.v2.api.records.TaskType;
+import org.apache.hadoop.util.ApplicationClassLoader;
 import org.apache.hadoop.util.Shell;
 import org.apache.hadoop.util.StringInterner;
 import org.apache.hadoop.util.StringUtils;
@@ -67,7 +69,6 @@
 import org.apache.hadoop.yarn.api.records.LocalResourceVisibility;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
-import org.apache.hadoop.yarn.util.ApplicationClassLoader;
 import org.apache.hadoop.yarn.util.Apps;
 import org.apache.hadoop.yarn.util.ConverterUtils;
 import org.apache.log4j.RollingFileAppender;

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/util/TestMRApps.java

@@ -50,6 +50,7 @@
 import org.apache.hadoop.mapreduce.v2.api.records.TaskId;
 import org.apache.hadoop.mapreduce.v2.api.records.TaskState;
 import org.apache.hadoop.mapreduce.v2.api.records.TaskType;
+import org.apache.hadoop.util.ApplicationClassLoader;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.yarn.api.ApplicationConstants;
 import org.apache.hadoop.util.StringUtils;
@@ -59,7 +60,6 @@
 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;
@@ -510,7 +510,8 @@ public void testTaskStateUI() {
   @Test
   public void testSystemClasses() {
     final List<String> systemClasses =
-        Arrays.asList(MRApps.getSystemClasses(new Configuration()));
+        Arrays.asList(StringUtils.getTrimmedStrings(
+        ApplicationClassLoader.DEFAULT_SYSTEM_CLASSES));
     for (String defaultXml : DEFAULT_XMLS) {
       assertTrue(defaultXml + " must be system resource",
           ApplicationClassLoader.isSystemClass(defaultXml, systemClasses));

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml

@@ -1660,13 +1660,13 @@
 
 <property>
    <name>mapreduce.job.classloader.system.classes</name>
-   <value>java.,javax.,org.w3c.dom.,org.xml.sax.,org.apache.commons.logging.,
+   <value></value>
-          org.apache.log4j.,org.apache.hadoop.,core-default.xml,
+  <description>Used to override the default definition of the system classes for
-          hdfs-default.xml,mapred-default.xml,yarn-default.xml</value>
+    the job classloader. The system classes are a comma-separated list of
-  <description>A comma-separated list of classes that should be loaded from the
+    classes that should be loaded from the system classpath, not the
-    system classpath, not the user-supplied JARs, when mapreduce.job.classloader
+    user-supplied JARs, when mapreduce.job.classloader is enabled. Names ending
-    is enabled. Names ending in '.' (period) are treated as package names,
+    in '.' (period) are treated as package names, and names starting with a '-'
-    and names starting with a '-' are treated as negative matches.
+    are treated as negative matches.
   </description>
 </property>
 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/v2/TestMRJobs.java

@@ -84,13 +84,13 @@
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.TokenIdentifier;
+import org.apache.hadoop.util.ApplicationClassLoader;
 import org.apache.hadoop.util.JarFinder;
 import org.apache.hadoop.util.Shell;
 import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.api.records.ContainerId;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppState;
-import org.apache.hadoop.yarn.util.ApplicationClassLoader;
 import org.apache.hadoop.yarn.util.ConverterUtils;
 import org.apache.log4j.Level;
 import org.junit.AfterClass;
@@ -242,8 +242,7 @@ private void testJobClassloader(boolean useCustomClasses) throws IOException,
       // to test AM loading user classes such as output format class, we want
       // to blacklist them from the system classes (they need to be prepended
       // as the first match wins)
-      String systemClasses =
+      String systemClasses = ApplicationClassLoader.DEFAULT_SYSTEM_CLASSES;
-          sleepConf.get(MRJobConfig.MAPREDUCE_JOB_CLASSLOADER_SYSTEM_CLASSES);
       // exclude the custom classes from system classes
       systemClasses = "-" + CustomOutputFormat.class.getName() + ",-" +
           CustomSpeculator.class.getName() + "," +

hadoop-yarn-project/hadoop-yarn/dev-support/findbugs-exclude.xml

@@ -344,4 +344,11 @@
       <Class name="org.apache.hadoop.yarn.server.resourcemanager.security.authorize.RMPolicyProvider"/>
       <Bug pattern="DC_DOUBLECHECK" />
   </Match>
+
+  <!-- ApplicationClassLoader is deprecated and moved to hadoop-common; ignore
+       warning on the identical name as it should be removed later -->
+  <Match>
+    <Class name="org.apache.hadoop.yarn.util.ApplicationClassLoader"/>
+    <Bug pattern="NM_SAME_SIMPLE_NAME_AS_SUPERCLASS"/>
+  </Match>
 </FindBugsFilter>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/ApplicationClassLoader.java

@@ -18,180 +18,30 @@
 
 package org.apache.hadoop.yarn.util;
 
-import java.io.File;
-import java.io.FilenameFilter;
 import java.net.MalformedURLException;
 import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience.Public;
 import org.apache.hadoop.classification.InterfaceStability.Unstable;
 
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Splitter;
-
 /**
- * A {@link URLClassLoader} for YARN application isolation. Classes from
+ * This type has been deprecated in favor of
- * the application JARs are loaded in preference to the parent loader.
+ * {@link org.apache.hadoop.util.ApplicationClassLoader}. All new uses of
+ * ApplicationClassLoader should use that type instead.
  */
 @Public
 @Unstable
-public class ApplicationClassLoader extends URLClassLoader {
+@Deprecated
-
+public class ApplicationClassLoader extends
-  private static final Log LOG =
+    org.apache.hadoop.util.ApplicationClassLoader {
-    LogFactory.getLog(ApplicationClassLoader.class.getName());
-  
-  private static final FilenameFilter JAR_FILENAME_FILTER =
-    new FilenameFilter() {
-      @Override
-      public boolean accept(File dir, String name) {
-        return name.endsWith(".jar") || name.endsWith(".JAR");
-      }
-  };
-  
-  private ClassLoader parent;
-  private List<String> systemClasses;
-
   public ApplicationClassLoader(URL[] urls, ClassLoader parent,
       List<String> systemClasses) {
-    super(urls, parent);
+    super(urls, parent, systemClasses);
-    this.parent = parent;
-    if (parent == null) {
-      throw new IllegalArgumentException("No parent classloader!");
-    }
-    this.systemClasses = systemClasses;
   }
-  
+
   public ApplicationClassLoader(String classpath, ClassLoader parent,
       List<String> systemClasses) throws MalformedURLException {
-    this(constructUrlsFromClasspath(classpath), parent, systemClasses);
+    super(classpath, parent, systemClasses);
   }
-  
+}
-  @VisibleForTesting
-  static URL[] constructUrlsFromClasspath(String classpath)
-      throws MalformedURLException {
-    List<URL> urls = new ArrayList<URL>();
-    for (String element : Splitter.on(File.pathSeparator).split(classpath)) {
-      if (element.endsWith("/*")) {
-        String dir = element.substring(0, element.length() - 1);
-        File[] files = new File(dir).listFiles(JAR_FILENAME_FILTER);
-        if (files != null) {
-          for (File file : files) {
-            urls.add(file.toURI().toURL());
-          }
-        }
-      } else {
-        File file = new File(element);
-        if (file.exists()) {
-          urls.add(new File(element).toURI().toURL());
-        }
-      }
-    }
-    return urls.toArray(new URL[urls.size()]);
-  }
-
-  @Override
-  public URL getResource(String name) {
-    URL url = null;
-    
-    if (!isSystemClass(name, systemClasses)) {
-      url= findResource(name);
-      if (url == null && name.startsWith("/")) {
-        if (LOG.isDebugEnabled()) {
-          LOG.debug("Remove leading / off " + name);
-        }
-        url= findResource(name.substring(1));
-      }
-    }
-
-    if (url == null) {
-      url= parent.getResource(name);
-    }
-
-    if (url != null) {
-      if (LOG.isDebugEnabled()) {
-        LOG.debug("getResource("+name+")=" + url);
-      }
-    }
-    
-    return url;
-  }
-
-  @Override
-  public Class<?> loadClass(String name) throws ClassNotFoundException {
-    return this.loadClass(name, false);
-  }
-
-  @Override
-  protected synchronized Class<?> loadClass(String name, boolean resolve)
-      throws ClassNotFoundException {
-    
-    if (LOG.isDebugEnabled()) {
-      LOG.debug("Loading class: " + name);
-    }
-
-    Class<?> c = findLoadedClass(name);
-    ClassNotFoundException ex = null;
-
-    if (c == null && !isSystemClass(name, systemClasses)) {
-      // Try to load class from this classloader's URLs. Note that this is like
-      // the servlet spec, not the usual Java 2 behaviour where we ask the
-      // parent to attempt to load first.
-      try {
-        c = findClass(name);
-        if (LOG.isDebugEnabled() && c != null) {
-          LOG.debug("Loaded class: " + name + " ");
-        }
-      } catch (ClassNotFoundException e) {
-        if (LOG.isDebugEnabled()) {
-          LOG.debug(e);
-        }
-        ex = e;
-      }
-    }
-
-    if (c == null) { // try parent
-      c = parent.loadClass(name);
-      if (LOG.isDebugEnabled() && c != null) {
-        LOG.debug("Loaded class from parent: " + name + " ");
-      }
-    }
-
-    if (c == null) {
-      throw ex != null ? ex : new ClassNotFoundException(name);
-    }
-
-    if (resolve) {
-      resolveClass(c);
-    }
-
-    return c;
-  }
-
-  @VisibleForTesting
-  public static boolean isSystemClass(String name, List<String> systemClasses) {
-    if (systemClasses != null) {
-      String canonicalName = name.replace('/', '.');
-      while (canonicalName.startsWith(".")) {
-        canonicalName=canonicalName.substring(1);
-      }
-      for (String c : systemClasses) {
-        boolean result = true;
-        if (c.startsWith("-")) {
-          c = c.substring(1);
-          result = false;
-        }
-        if (c.endsWith(".") && canonicalName.startsWith(c)) {
-          return result;
-        } else if (canonicalName.equals(c)) {
-          return result;
-        }
-      }
-    }
-    return false;
-  }
-}