HADOOP-6105. Adds support for automatically handling deprecation of configuration keys. Contributed by V.V.Chaitanya Krishna.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@812078 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -171,6 +171,9 @@ Trunk (unreleased changes)
 
     HADOOP-6165. Add metadata to Serializations. (tomwhite)
 
+    HADOOP-6105. Adds support for automatically handling deprecation of
+    configuration keys. (V.V.Chaitanya Krishna via yhemanth)
+    
   IMPROVEMENTS
 
     HADOOP-4565. Added CombineFileInputFormat to use data locality information

src/java/core-default.xml

@@ -486,6 +486,10 @@
   </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

@@ -44,6 +44,7 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.StringTokenizer;
 import java.util.WeakHashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -182,6 +183,141 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
    */
   private HashMap<String, String> updatingResource;
   
+  /**
+   * Class to keep the information about the keys which replace the deprecated
+   * ones.
+   * 
+   * This class stores the new keys which replace the deprecated keys and also
+   * gives a provision to have a custom message for each of the deprecated key
+   * that is being replaced. It also provides method to get the appropriate
+   * warning message which can be logged whenever the deprecated key is used.
+   */
+  private static class DeprecatedKeyInfo {
+    private String[] newKeys;
+    private String customMessage;
+    private boolean accessed;
+    DeprecatedKeyInfo(String[] newKeys, String customMessage) {
+      this.newKeys = newKeys;
+      this.customMessage = customMessage;
+      accessed = false;
+    }
+    DeprecatedKeyInfo(String[] newKeys) {
+      this(newKeys, null);
+    }
+
+    /**
+     * Method to provide the warning message. It gives the custom message if
+     * non-null, and default message otherwise.
+     * @param key the associated deprecated key.
+     * @return message that is to be logged when a deprecated key is used.
+     */
+    private final String getWarningMessage(String key) {
+      String warningMessage;
+      if(customMessage == null) {
+        StringBuilder message = new StringBuilder(key);
+        String deprecatedKeySuffix = " is deprecated. Instead, use ";
+        message.append(deprecatedKeySuffix);
+        for (int i = 0; i < newKeys.length; i++) {
+          message.append(newKeys[i]);
+          if(i != newKeys.length-1) {
+            message.append(", ");
+          }
+        }
+        warningMessage = message.toString();
+      }
+      else {
+        warningMessage = customMessage;
+      }
+      accessed = true;
+      return warningMessage;
+    }
+  }
+  
+  /**
+   * Stores the deprecated keys, the new keys which replace the deprecated keys
+   * and custom message(if any provided).
+   */
+  private static Map<String, DeprecatedKeyInfo> deprecatedKeyMap = 
+    new HashMap<String, DeprecatedKeyInfo>();
+  
+  /**
+   * Adds the deprecated key to the deprecation map.
+   * It does not override any existing entries in the deprecation map.
+   * This is to be used only by the developers in order to add deprecation of
+   * keys, and attempts to call this method after loading resources once,
+   * would lead to <tt>UnsupportedOperationException</tt>
+   * @param key
+   * @param newKeys
+   * @param customMessage
+   */
+  public synchronized static void addDeprecation(String key, String[] newKeys,
+      String customMessage) {
+    if (key == null || key.length() == 0 ||
+        newKeys == null || newKeys.length == 0) {
+      throw new IllegalArgumentException();
+    }
+    if (!isDeprecated(key)) {
+      DeprecatedKeyInfo newKeyInfo;
+      if (customMessage == null) {
+        newKeyInfo = new DeprecatedKeyInfo(newKeys);
+      }
+      else {
+        newKeyInfo = new DeprecatedKeyInfo(newKeys, customMessage);
+      }
+      deprecatedKeyMap.put(key, newKeyInfo);
+    }
+  }
+
+  /**
+   * Adds the deprecated key to the deprecation map when no custom message
+   * is provided.
+   * It does not override any existing entries in the deprecation map.
+   * This is to be used only by the developers in order to add deprecation of
+   * keys, and attempts to call this method after loading resources once,
+   * would lead to <tt>UnsupportedOperationException</tt>
+   * 
+   * @param key Key that is to be deprecated
+   * @param newKeys list of keys that take up the values of deprecated key
+   */
+  public synchronized static void addDeprecation(String key, String[] newKeys) {
+    addDeprecation(key, newKeys, null);
+  }
+  
+  /**
+   * checks whether the given <code>key</code> is deprecated.
+   * 
+   * @param key the parameter which is to be checked for deprecation
+   * @return <code>true</code> if the key is deprecated and 
+   *         <code>false</code> otherwise.
+   */
+  private static boolean isDeprecated(String key) {
+    return deprecatedKeyMap.containsKey(key);
+  }
+ 
+  /**
+   * Checks for the presence of the property <code>name</code> in the
+   * deprecation map. Returns the first of the list of new keys if present
+   * in the deprecation map or the <code>name</code> itself.
+   * @param name the property name
+   * @return the first property in the list of properties mapping
+   *         the <code>name</code> or the <code>name</code> itself.
+   */
+  private String handleDeprecation(String name) {
+    if (isDeprecated(name)) {
+      DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(name);
+      if (!keyInfo.accessed) {
+        LOG.warn(keyInfo.getWarningMessage(name));
+      }
+      for (String newKey : keyInfo.newKeys) {
+        if(newKey != null) {
+          name = newKey;
+          break;
+        }
+      }
+    }
+    return name;
+  }
+  
   static{
     //print deprecation warning if hadoop-site.xml is found in classpath
     ClassLoader cL = Thread.currentThread().getContextClassLoader();
@@ -405,41 +541,61 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
   
   /**
    * Get the value of the <code>name</code> property, <code>null</code> if
-   * no such property exists.
+   * no such property exists. If the key is deprecated, it returns the value of
+   * the first key which replaces the deprecated key and is not null
    * 
    * Values are processed for <a href="#VariableExpansion">variable expansion</a> 
    * before being returned. 
    * 
    * @param name the property name.
-   * @return the value of the <code>name</code> property, 
+   * @return the value of the <code>name</code> or its replacing property, 
    *         or null if no such property exists.
    */
   public String get(String name) {
+    name = handleDeprecation(name);
     return substituteVars(getProps().getProperty(name));
   }
 
   /**
    * Get the value of the <code>name</code> property, without doing
-   * <a href="#VariableExpansion">variable expansion</a>.
+   * <a href="#VariableExpansion">variable expansion</a>.If the key is 
+   * deprecated, it returns the value of the first key which replaces 
+   * the deprecated key and is not null.
    * 
    * @param name the property name.
-   * @return the value of the <code>name</code> property, 
+   * @return the value of the <code>name</code> property or 
-   *         or null if no such property exists.
+   *         its replacing property and null if no such property exists.
    */
   public String getRaw(String name) {
+    name = handleDeprecation(name);
     return getProps().getProperty(name);
   }
 
   /** 
-   * Set the <code>value</code> of the <code>name</code> property.
+   * Set the <code>value</code> of the <code>name</code> property. If 
+   * <code>name</code> is deprecated, it sets the <code>value</code> to the keys
+   * that replace the deprecated key.
    * 
    * @param name property name.
    * @param value property value.
    */
   public void set(String name, String value) {
+    if (deprecatedKeyMap.isEmpty()) {
+      getProps();
+    }
+    if (!isDeprecated(name)) {
       getOverlay().setProperty(name, value);
       getProps().setProperty(name, value);
     }
+    else {
+      DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(name);
+      LOG.warn(keyInfo.getWarningMessage(name));
+      for (String newKey : keyInfo.newKeys) {
+        getOverlay().setProperty(newKey, value);
+        getProps().setProperty(newKey, value);
+      }
+    }
+  }
   
   /**
    * Sets a property if it is currently unset.
@@ -460,8 +616,11 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
   }
 
   /** 
-   * Get the value of the <code>name</code> property. If no such property 
+   * Get the value of the <code>name</code>. If the key is deprecated,
-   * exists, then <code>defaultValue</code> is returned.
+   * it returns the value of the first key which replaces the deprecated key
+   * and is not null.
+   * If no such property exists,
+   * then <code>defaultValue</code> is returned.
    * 
    * @param name property name.
    * @param defaultValue default value.
@@ -469,6 +628,7 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
    *         doesn't exist.                    
    */
   public String get(String name, String defaultValue) {
+    name = handleDeprecation(name);
     return substituteVars(getProps().getProperty(name, defaultValue));
   }
     
@@ -1180,6 +1340,108 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
     for (Object resource : resources) {
       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.
+   */
+  private void processDeprecatedKeys() {
+    for (Map.Entry<String, DeprecatedKeyInfo> item : 
+      deprecatedKeyMap.entrySet()) {
+      if (!properties.containsKey(item.getKey())) {
+        continue;
+      }
+      String oldKey = item.getKey();
+      deprecatedKeyMap.get(oldKey).accessed = false;
+      setDeprecatedValue(oldKey, properties.getProperty(oldKey),
+          finalParameters.contains(oldKey));
+      properties.remove(oldKey);
+      if (finalParameters.contains(oldKey)) {
+        finalParameters.remove(oldKey);
+      }
+      if (storeResource) {
+        updatingResource.remove(oldKey);
+      }
+    }
+  }
+  
+  /**
+   * Sets the deprecated key's value to the associated mapped keys
+   * @param attr the deprecated key
+   * @param value the value corresponding to the deprecated key
+   * @param finalParameter flag to indicate if <code>attr</code> is
+   *        marked as final
+   */
+  private void setDeprecatedValue(String attr,
+      String value, boolean finalParameter) {
+    DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(attr);
+    for (String key:keyInfo.newKeys) {
+      // update replacing keys with deprecated key's value in all cases,
+      // except when the replacing key is already set to final
+      // and finalParameter is false
+      if (finalParameters.contains(key) && !finalParameter) {
+        LOG.warn("An attempt to override final parameter: "+key
+            +";  Ignoring.");
+        continue;
+      }
+      properties.setProperty(key, value);
+      if (storeResource) {
+        updatingResource.put(key, updatingResource.get(attr));
+      }
+      if (finalParameter) {
+        finalParameters.add(key);
+      }
+    }
   }
   
   private void loadResource(Properties properties, Object name, boolean quiet) {

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

@@ -0,0 +1,312 @@
+/**
+ * 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.conf;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+
+import org.apache.hadoop.fs.Path;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+ 
+public class TestConfigurationDeprecation {
+  private Configuration conf;
+  final static String CONFIG = new File("./test-config.xml").getAbsolutePath();
+  final static String CONFIG2 = 
+    new File("./test-config2.xml").getAbsolutePath();
+  final static String CONFIG3 = 
+    new File("./test-config3.xml").getAbsolutePath();
+  BufferedWriter out;
+
+  @Before
+  public void setUp() throws Exception {
+    conf = new Configuration(false);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    new File(CONFIG).delete();
+    new File(CONFIG2).delete();
+    new File(CONFIG3).delete();
+  }
+  
+  private void startConfig() throws IOException{
+    out.write("<?xml version=\"1.0\"?>\n");
+    out.write("<configuration>\n");
+  }
+
+  private void endConfig() throws IOException{
+    out.write("</configuration>\n");
+    out.close();
+  }
+
+  void appendProperty(String name, String val) throws IOException {
+    appendProperty(name, val, false);
+  }
+ 
+  void appendProperty(String name, String val, boolean isFinal)
+    throws IOException {
+    out.write("<property>");
+    out.write("<name>");
+    out.write(name);
+    out.write("</name>");
+    out.write("<value>");
+    out.write(val);
+    out.write("</value>");
+    if (isFinal) {
+      out.write("<final>true</final>");
+    }
+    out.write("</property>\n");
+  }
+  
+  static class MyConf extends Configuration {
+    static {
+      // add deprecation mappings.
+      Configuration.addDeprecation("old.key1", new String[]{"new.key1"});
+      Configuration.addDeprecation("old.key2", new String[]{"new.key2"});
+      Configuration.addDeprecation("old.key3", new String[]{"new.key3"});
+      Configuration.addDeprecation("old.key4", new String[]{"new.key4"});
+      Configuration.addDeprecation("old.key5", new String[]{"new.key5"});
+      Configuration.addDeprecation("old.key6", new String[]{"new.key6"});
+      Configuration.addDeprecation("old.key7", new String[]{"new.key7"});
+      Configuration.addDeprecation("old.key8", new String[]{"new.key8"});
+      Configuration.addDeprecation("old.key9", new String[]{"new.key9"});
+      Configuration.addDeprecation("old.key10", new String[]{"new.key10"});
+      Configuration.addDeprecation("old.key11", new String[]{"new.key11"});
+      Configuration.addDeprecation("old.key12", new String[]{"new.key12"});
+      Configuration.addDeprecation("old.key13", new String[]{"new.key13"});
+      Configuration.addDeprecation("old.key14", new String[]{"new.key14"});
+      Configuration.addDeprecation("old.key15", new String[]{"new.key15"});
+      Configuration.addDeprecation("old.key16", new String[]{"new.key16"});
+      Configuration.addDeprecation("A", new String[]{"B"});
+      Configuration.addDeprecation("C", new String[]{"D"});
+      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 
+   * deprecation.Based on the order of occurrence of deprecated key and 
+   * its corresponding mapping key, various cases arise.
+   * The precedence order being followed is:
+   * 1. Final Parameter 
+   * 2. Deprecated key's value.
+   * @throws IOException 
+   * 
+   * @throws IOException
+   * @throws ClassNotFoundException 
+   */
+  @Test
+  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);
+    appendProperty("new.key2","default.value2");
+    appendProperty("new.key3","default.value3",true);
+    appendProperty("new.key4","default.value4");
+    appendProperty("new.key5","default.value5",true);
+    appendProperty("new.key6","default.value6");
+    appendProperty("new.key7","default.value7",true);
+    appendProperty("new.key8","default.value8");
+    appendProperty("new.key9","default.value9");
+    appendProperty("new.key10","default.value10");
+    appendProperty("new.key11","default.value11");
+    appendProperty("new.key12","default.value12");
+    appendProperty("new.key13","default.value13");
+    appendProperty("new.key14","default.value14");
+    appendProperty("new.key15","default.value15");
+    appendProperty("new.key16","default.value16");
+    endConfig();
+    Path fileResource = new Path(CONFIG);
+    conf.addResource(fileResource);
+    
+    out=new BufferedWriter(new FileWriter(CONFIG2));
+    startConfig();
+    // add keys that are tested while they are loaded just after their 
+    // corresponding default values
+    appendProperty("old.key1","old.value1",true);
+    appendProperty("old.key2","old.value2",true);
+    appendProperty("old.key3","old.value3");
+    appendProperty("old.key4","old.value4");
+    appendProperty("new.key5","new.value5",true);
+    appendProperty("new.key6","new.value6",true);
+    appendProperty("new.key7","new.value7");
+    appendProperty("new.key8","new.value8");
+    
+    // add keys that are tested while they are loaded first and are followed by
+    // loading of their corresponding deprecated or replacing key
+    appendProperty("new.key9","new.value9",true);
+    appendProperty("new.key10","new.value10");
+    appendProperty("new.key11","new.value11",true);
+    appendProperty("new.key12","new.value12");
+    appendProperty("old.key13","old.value13",true);
+    appendProperty("old.key14","old.value14");
+    appendProperty("old.key15","old.value15",true);
+    appendProperty("old.key16","old.value16");
+    endConfig();
+    Path fileResource1 = new Path(CONFIG2);
+    conf.addResource(fileResource1);
+    
+    out=new BufferedWriter(new FileWriter(CONFIG3));
+    startConfig();
+    // add keys which are already loaded by the corresponding replacing or 
+    // deprecated key.
+    appendProperty("old.key9","old.value9",true);
+    appendProperty("old.key10","old.value10",true);
+    appendProperty("old.key11","old.value11");
+    appendProperty("old.key12","old.value12");
+    appendProperty("new.key13","new.value13",true);
+    appendProperty("new.key14","new.value14",true);
+    appendProperty("new.key15","new.value15");
+    appendProperty("new.key16","new.value16");
+    appendProperty("B", "valueB");
+    endConfig();
+    Path fileResource2 = new Path(CONFIG3);
+    conf.addResource(fileResource2);
+    
+    // get the values. Also check for consistency in get of old and new keys, 
+    // when they are set to final or non-final
+    // Key - the key that is being loaded
+    // isFinal - true if the key is marked as final
+    // prev.occurrence - key that most recently loaded the current key 
+    //                   with its value.
+    // isPrevFinal - true if key corresponding to 
+    //               prev.occurrence is marked as final.
+    
+    // Key-deprecated , isFinal-true, prev.occurrence-default.xml,
+    // isPrevFinal-true
+    assertEquals("old.value1", conf.get("new.key1"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key1"), conf.get("new.key1"));
+    // Key-deprecated , isFinal-true, prev.occurrence-default.xml,
+    // isPrevFinal-false
+    assertEquals("old.value2", conf.get("new.key2"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key2"), conf.get("new.key2"));
+    // Key-deprecated , isFinal-false, prev.occurrence-default.xml,
+    // isPrevFinal-true
+    assertEquals("default.value3", conf.get("new.key3"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key3"), conf.get("new.key3"));
+    // Key-deprecated , isFinal-false, prev.occurrence-default.xml,
+    // isPrevFinal-false
+    assertEquals("old.value4", conf.get("new.key4"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key4"), conf.get("new.key4"));
+    // Key-site.xml , isFinal-true, prev.occurrence-default.xml,
+    // isPrevFinal-true
+    assertEquals("default.value5", conf.get("new.key5"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key5"), conf.get("new.key5"));
+    // Key-site.xml , isFinal-true, prev.occurrence-default.xml,
+    // isPrevFinal-false
+    assertEquals("new.value6",conf.get("new.key6"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key6"), conf.get("new.key6"));
+    // Key-site.xml , isFinal-false, prev.occurrence-default.xml,
+    // isPrevFinal-true
+    assertEquals("default.value7", conf.get("new.key7"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key7"), conf.get("new.key7"));
+    // Key-site.xml , isFinal-false, prev.occurrence-default.xml,
+    // isPrevFinal-false
+    assertEquals("new.value8",conf.get("new.key8"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key8"), conf.get("new.key8"));
+    // Key-deprecated , isFinal-true, prev.occurrence-site.xml,
+    // isPrevFinal-true
+    assertEquals("old.value9", conf.get("new.key9"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key9"), conf.get("new.key9"));
+    // Key-deprecated , isFinal-true, prev.occurrence-site.xml,
+    // isPrevFinal-false
+    assertEquals("old.value10", conf.get("new.key10"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key10"), conf.get("new.key10"));
+    // Key-deprecated , isFinal-false, prev.occurrence-site.xml,
+    // isPrevFinal-true
+    assertEquals("new.value11", conf.get("new.key11"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key11"), conf.get("new.key11"));
+    // Key-deprecated , isFinal-false, prev.occurrence-site.xml,
+    // isPrevFinal-false
+    assertEquals("old.value12", conf.get("new.key12"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key12"), conf.get("new.key12"));
+    // Key-site.xml , isFinal-true, prev.occurrence-deprecated,
+    // isPrevFinal-true
+    assertEquals("old.value13", conf.get("new.key13"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key13"), conf.get("new.key13"));
+    // Key-site.xml , isFinal-true, prev.occurrence-deprecated,
+    // isPrevFinal-false
+    assertEquals("new.value14", conf.get("new.key14"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key14"), conf.get("new.key14"));
+    // Key-site.xml , isFinal-false, prev.occurrence-deprecated,
+    // isPrevFinal-true
+    assertEquals("old.value15", conf.get("new.key15"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key15"), conf.get("new.key15"));
+    // Key-site.xml , isFinal-false, prev.occurrence-deprecated,
+    // isPrevFinal-false
+    assertEquals("old.value16", conf.get("new.key16"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("old.key16"), conf.get("new.key16"));
+    
+    // ensure that reloadConfiguration doesn't deprecation information
+    conf.reloadConfiguration();
+    assertEquals(conf.get("A"), "valueB");
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("A"), conf.get("B"));
+    
+    // check for consistency in get and set of deprecated and corresponding 
+    // new keys from the user code
+    // set old key
+    conf.set("C", "valueC");
+    // get new key
+    assertEquals("valueC",conf.get("D"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("C"), conf.get("D"));
+    
+    // set new key
+    conf.set("F","valueF");
+    // get old key
+    assertEquals("valueF", conf.get("E"));
+    // check consistency in get of old and new keys
+    assertEquals(conf.get("E"), conf.get("F"));
+    
+    conf.set("G", "valueG");
+    assertEquals("valueG", conf.get("G"));
+    assertEquals("valueG", conf.get("H"));
+    assertEquals("valueG", conf.get("I"));
+  }
+
+}