HADOOP-6243. Fix a NullPointerException in processing deprecated keys. Contributed by Sreekanth Ramakrishnan.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@812455 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -984,6 +984,9 @@ Trunk (unreleased changes)
     HADOOP-6229. Attempt to make a directory under an existing file on
     LocalFileSystem should throw an Exception. (Boris Shkolnik via tomwhite)
 
+    HADOOP-6243. Fix a NullPointerException in processing deprecated keys.
+    (Sreekanth Ramakrishnan via yhemanth)
+
 Release 0.20.1 - Unreleased
 
   INCOMPATIBLE CHANGES

src/java/core-default.xml

@@ -485,11 +485,4 @@
     IP address.
   </description>
 </property>
-
-<property>
-  <name>hadoop.conf.extra.classes</name>
-  <value>org.apache.hadoop.mapred.JobConf</value>
-  <final>true</final>
-</property>
-
 </configuration>

src/java/org/apache/hadoop/conf/Configuration.java

@@ -336,6 +336,12 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
     }
     addDefaultResource("core-default.xml");
     addDefaultResource("core-site.xml");
+    //Add code for managing deprecated key mapping
+    //for example
+    //addDeprecation("oldKey1",new String[]{"newkey1","newkey2"});
+    //adds deprecation for oldKey1 to two new keys(newkey1, newkey2).
+    //so get or set of oldKey1 will correctly populate/access values of 
+    //newkey1 and newkey2
   }
   
   private Properties properties;
@@ -1364,56 +1370,8 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
       loadResource(properties, resource, quiet);
     }
     // process for deprecation.
-    processDeprecation();
-  }
-  
-  /**
-   * Flag to ensure that the classes mentioned in the value of the property
-   * <code>hadoop.conf.extra.classes</code> are loaded only once for
-   * all instances of <code>Configuration</code>
-   */
-  private static AtomicBoolean loadedDeprecation = new AtomicBoolean(false);
-  
-  private static final String extraConfKey = "hadoop.conf.extra.classes";
-
-  /**
-   * adds all the deprecations to the deprecatedKeyMap and updates the values of
-   * the appropriate keys
-   */
-  private void processDeprecation() {
-    populateDeprecationMapping();
     processDeprecatedKeys();
   }
-  
-  /**
-   * Loads all the classes in mapred and hdfs that extend Configuration and that
-   * have deprecations to be added into deprecatedKeyMap
-   */
-  private synchronized void populateDeprecationMapping() {
-    if (!loadedDeprecation.get()) {
-      // load classes from mapred and hdfs which extend Configuration and have 
-      // deprecations added in their static blocks
-      String classnames = substituteVars(properties.getProperty(extraConfKey));
-      if (classnames == null) {
-        return;
-      }
-      String[] classes = StringUtils.getStrings(classnames);
-      for (String className : classes) {
-        try {
-          Class.forName(className);
-        } catch (ClassNotFoundException e) {
-          LOG.warn(className + " is not in the classpath");
-        }
-      }
-      // make deprecatedKeyMap unmodifiable in order to prevent changes to 
-      // it in user's code.
-      deprecatedKeyMap = Collections.unmodifiableMap(deprecatedKeyMap);
-      // ensure that deprecation processing is done only once for all 
-      // instances of this object
-      loadedDeprecation.set(true);
-    }
-  }
-
   /**
    * Updates the keys that are replacing the deprecated keys and removes the 
    * deprecated keys from memory.

src/test/core/org/apache/hadoop/conf/TestConfigurationDeprecation.java

@@ -81,9 +81,7 @@ public class TestConfigurationDeprecation {
     out.write("</property>\n");
   }
   
-  static class MyConf extends Configuration {
-    static {
-      // add deprecation mappings.
+  private void addDeprecationToConfiguration() {
     Configuration.addDeprecation("old.key1", new String[]{"new.key1"});
     Configuration.addDeprecation("old.key2", new String[]{"new.key2"});
     Configuration.addDeprecation("old.key3", new String[]{"new.key3"});
@@ -105,7 +103,6 @@ public class TestConfigurationDeprecation {
     Configuration.addDeprecation("E", new String[]{"F"});
     Configuration.addDeprecation("G", new String[]{"H","I"});
   }
-  }
   
   /**
    * This test is to check the precedence order between being final and 
@@ -123,8 +120,6 @@ public class TestConfigurationDeprecation {
   public void testDeprecation() throws IOException {
     out=new BufferedWriter(new FileWriter(CONFIG));
     startConfig();
-    appendProperty("hadoop.conf.extra.classes", MyConf.class.getName()
-        + ",myconf1");
     // load keys with default values. Some of them are set to final to
     // test the precedence order between deprecation and being final
     appendProperty("new.key1","default.value1",true);
@@ -145,6 +140,7 @@ public class TestConfigurationDeprecation {
     appendProperty("new.key16","default.value16");
     endConfig();
     Path fileResource = new Path(CONFIG);
+    addDeprecationToConfiguration();
     conf.addResource(fileResource);
     
     out=new BufferedWriter(new FileWriter(CONFIG2));