Clean up dead code.

Change-Id: Ic3b9258abecc3372ed13afbf627a578e9894d857

Author: smengcl

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FsTracer.java

@@ -47,20 +47,6 @@ public static synchronized Tracer get(Configuration conf) {
     return instance;
   }
 
-  @VisibleForTesting
-  public static synchronized void clear() {
-/*
-    if (instance == null) {
-      return;
-    }
-    try {
-      instance.close();
-    } finally {
-      instance = null;
-    }
- */
-  }
-
   private FsTracer() {
   }
 }

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/datatransfer/DataTransferProtoUtil.java

@@ -98,16 +98,6 @@ static BaseHeaderProto buildBaseHeader(ExtendedBlock blk,
     return builder.build();
   }
 
-  /*
-  public static SpanId fromProto(DataTransferTraceInfoProto proto) {
-    if ((proto != null) && proto.hasTraceId() &&
-          proto.hasParentId()) {
-      return new SpanId(proto.getTraceId(), proto.getParentId());
-    }
-    return null;
-  }
-  */
-
   public static void checkBlockOpStatus(
           BlockOpResponseProto response,
           String logInfo) throws IOException {

hadoop-hdfs-project/hadoop-hdfs-client/src/test/java/org/apache/hadoop/hdfs/TestDFSPacket.java

@@ -65,31 +65,4 @@ public static void assertArrayRegionsEqual(byte []buf1, int off1, byte []buf2,
       }
     }
   }
-
-  /*
-  @Test
-  public void testAddParentsGetParents() throws Exception {
-    DFSPacket p = new DFSPacket(null, maxChunksPerPacket,
-                                0, 0, checksumSize, false);
-    SpanId parents[] = p.getTraceParents();
-    Assert.assertEquals(0, parents.length);
-    p.addTraceParent(new SpanId(0, 123));
-    p.addTraceParent(new SpanId(0, 123));
-    parents = p.getTraceParents();
-    Assert.assertEquals(1, parents.length);
-    Assert.assertEquals(new SpanId(0, 123), parents[0]);
-    parents = p.getTraceParents(); // test calling 'get' again.
-    Assert.assertEquals(1, parents.length);
-    Assert.assertEquals(new SpanId(0, 123), parents[0]);
-    p.addTraceParent(new SpanId(0, 1));
-    p.addTraceParent(new SpanId(0, 456));
-    p.addTraceParent(new SpanId(0, 789));
-    parents = p.getTraceParents();
-    Assert.assertEquals(4, parents.length);
-    Assert.assertEquals(new SpanId(0, 1), parents[0]);
-    Assert.assertEquals(new SpanId(0, 123), parents[1]);
-    Assert.assertEquals(new SpanId(0, 456), parents[2]);
-    Assert.assertEquals(new SpanId(0, 789), parents[3]);
-  }
-  */
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSOutputStream.java

@@ -295,7 +295,6 @@ public void testCongestionBackoff() throws IOException {
         Whitebox.getInternalState(stream, "congestedNodes");
     congestedNodes.add(mock(DatanodeInfo.class));
     DFSPacket packet = mock(DFSPacket.class);
-    //when(packet.getTraceParents()).thenReturn(new SpanId[] {});
     dataQueue.add(packet);
     stream.run();
     Assert.assertTrue(congestedNodes.isEmpty());