From 89be1f7237277d4038660913259a8965c33c4011 Mon Sep 17 00:00:00 2001
From: Jarek Jarcec Cecho <jarcec@apache.org>
Date: Mon, 5 Oct 2015 16:15:04 -0700
Subject: [PATCH] SQOOP-2602: Sqoop2: Static initialization of ClassUtils
 defaultClassloader is fragile

(Abraham Fine via Jarek Jarcec Cecho)
---
 .../org/apache/sqoop/utils/ClassUtils.java    | 24 ++++++++-----------
 .../apache/sqoop/utils/TestClassUtils.java    |  3 +--
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/common/src/main/java/org/apache/sqoop/utils/ClassUtils.java b/common/src/main/java/org/apache/sqoop/utils/ClassUtils.java
index ca438486..ed689884 100644
--- a/common/src/main/java/org/apache/sqoop/utils/ClassUtils.java
+++ b/common/src/main/java/org/apache/sqoop/utils/ClassUtils.java
@@ -50,14 +50,6 @@ public final class ClassUtils {
   private static final Class<?> NEGATIVE_CACHE_SENTINEL =
     NegativeCacheSentinel.class;
 
-  private static ClassLoader defaultClassLoader;
-  static {
-    defaultClassLoader = Thread.currentThread().getContextClassLoader();
-    if (defaultClassLoader == null) {
-      defaultClassLoader = ClassUtils.class.getClassLoader();
-    }
-  }
-
   /**
    * A unique class which is used as a sentinel value in the caching
    * for loadClass.
@@ -74,7 +66,7 @@ private static abstract class NegativeCacheSentinel {}
    * @return Class instance or NULL
    */
   public static Class<?> loadClass(String className) {
-    return loadClassWithClassLoader(className, defaultClassLoader);
+    return loadClassWithClassLoader(className, getClassLoader());
   }
 
   /**
@@ -139,7 +131,7 @@ public static Class<?> loadClassWithClassLoader(String className, ClassLoader lo
    * @return Instance of new class or NULL in case of any error
    */
   public static Object instantiate(String className, Object ... args) {
-    return instantiateWithClassLoader(className, defaultClassLoader, args);
+    return instantiateWithClassLoader(className, getClassLoader(), args);
   }
 
   /**
@@ -196,7 +188,7 @@ public static Object instantiate(Class klass, Object ... args) {
    * @return Path on local filesystem to jar where given jar is present
    */
   public static String jarForClass(String className) {
-    return jarForClassWithClassLoader(className, defaultClassLoader);
+    return jarForClassWithClassLoader(className, getClassLoader());
   }
 
   /**
@@ -223,7 +215,7 @@ public static String jarForClass(Class klass) {
     String jarPath = null;
     String class_file = klass.getName().replaceAll("\\.", "/") + ".class";
     try {
-      URL url = defaultClassLoader.getResource(class_file);
+      URL url = getClassLoader().getResource(class_file);
       String path = url.getPath();
       path = URLDecoder.decode(path, "UTF-8");
       if ("jar".equals(url.getProtocol())) {
@@ -271,8 +263,12 @@ public static void clearCache() {
     CACHE_CLASSES.clear();
   }
 
-  public static void setDefaultClassLoader(ClassLoader classLoader) {
-    defaultClassLoader = classLoader;
+  public static ClassLoader getClassLoader() {
+    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+    if (classLoader == null) {
+      classLoader = ClassUtils.class.getClassLoader();
+    }
+    return classLoader;
   }
 
   private ClassUtils() {
diff --git a/common/src/test/java/org/apache/sqoop/utils/TestClassUtils.java b/common/src/test/java/org/apache/sqoop/utils/TestClassUtils.java
index 8851440c..674ae6a5 100644
--- a/common/src/test/java/org/apache/sqoop/utils/TestClassUtils.java
+++ b/common/src/test/java/org/apache/sqoop/utils/TestClassUtils.java
@@ -60,10 +60,10 @@ public void captureClassLoader() throws Exception {
     File jarFile = compileAJar();
     URL[] urlArray = { jarFile.toURI().toURL() };
     URLClassLoader newClassLoader = new URLClassLoader(urlArray, classLoader);
-    ClassUtils.setDefaultClassLoader(newClassLoader);
     testAClass = newClassLoader.loadClass("A");
     testParentClass = newClassLoader.loadClass("Parent");
     testChildClass = newClassLoader.loadClass("Child");
+    Thread.currentThread().setContextClassLoader(newClassLoader);
   }
 
   private File compileAJar() throws Exception{
@@ -159,7 +159,6 @@ private void addFileToJar(File source, JarOutputStream target) throws Exception
   @AfterMethod
   public void restoreClassLoader() {
     Thread.currentThread().setContextClassLoader(classLoader);
-    ClassUtils.setDefaultClassLoader(classLoader);
   }
 
   @Test