HADOOP-17329. mvn site commands fails due to MetricsSystemImpl changes. Contributed by Xiaoqiao He.

(cherry picked from commit f17e067d527b0089124a8ca69b36fb20ed118c55)

hadoop-common-project/hadoop-common/dev-support/jdiff-workaround.patch

@@ -1,11 +1,12 @@
 diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java
-index a277abd..ed7c709 100644
+index a277abd6e13..1d131d5db6e 100644
 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java
 +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java
-@@ -43,18 +43,6 @@
+@@ -42,18 +42,6 @@
+   @InterfaceAudience.Private
    public abstract MetricsSystem init(String prefix);
 
-   /**
+-  /**
 -   * Register a metrics source
 -   * @param <T>   the actual type of the source object
 -   * @param source object to register
@@ -17,15 +18,11 @@ index a277abd..ed7c709 100644
 -   */
 -  public abstract <T> T register(String name, String desc, T source);
 -
--  /**
+   /**
     * Unregister a metrics source
     * @param name of the source. This is the name you use to call register()
-    */
-@@ -77,18 +65,19 @@
-    */
-   @InterfaceAudience.Private
+@@ -79,16 +67,16 @@
    public abstract MetricsSource getSource(String name);
-+
 
    /**
 -   * Register a metrics sink
@@ -50,10 +47,10 @@ index a277abd..ed7c709 100644
    /**
     * Register a callback interface for JMX events
 diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSystemImpl.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSystemImpl.java
-index 6986edb..eeea81f 100644
+index a6edf08e5a7..5b87be1ec67 100644
 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSystemImpl.java
 +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSystemImpl.java
-@@ -270,27 +270,6 @@ void registerSource(String name, String desc, MetricsSource source) {
+@@ -269,31 +269,6 @@ void registerSource(String name, String desc, MetricsSource source) {
      LOG.debug("Registered source "+ name);
    }
 
@@ -61,7 +58,11 @@ index 6986edb..eeea81f 100644
 -  T register(final String name, final String description, final T sink) {
 -    LOG.debug(name +", "+ description);
 -    if (allSinks.containsKey(name)) {
--      LOG.warn("Sink "+ name +" already exists!");
+-      if(sinks.get(name) == null) {
+-        registerSink(name, description, sink);
+-      } else {
+-        LOG.warn("Sink "+ name +" already exists!");
+-      }
 -      return sink;
 -    }
 -    allSinks.put(name, sink);
@@ -82,10 +83,10 @@ index 6986edb..eeea81f 100644
      checkNotNull(config, "config");
      MetricsConfig conf = sinkConfigs.get(name);
 diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/impl/TestGangliaMetrics.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/impl/TestGangliaMetrics.java
-index c19d238..f8412f1 100644
+index 7bc772f062a..f012c877d18 100644
 --- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/impl/TestGangliaMetrics.java
 +++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/impl/TestGangliaMetrics.java
-@@ -130,8 +130,8 @@ public void testTagsForPrefix() throws Exception {
+@@ -139,8 +139,8 @@ public void testTagsForPrefix() throws Exception {
      GangliaMetricsTestHelper.setDatagramSocket(gsink31, mockds31);
 
      // register the sinks