HDFS-13851. Remove AlignmentContext from AbstractNNFailoverProxyProvider. Contributed by Konstantin Shvachko.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/AbstractNNFailoverProxyProvider.java

@@ -34,7 +34,6 @@ import org.apache.hadoop.hdfs.DFSUtilClient;
 import org.apache.hadoop.hdfs.HAUtilClient;
 import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
 import org.apache.hadoop.io.retry.FailoverProxyProvider;
-import org.apache.hadoop.ipc.AlignmentContext;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -107,11 +106,7 @@ public abstract class AbstractNNFailoverProxyProvider<T> implements
     return fallbackToSimpleAuth;
   }
 
-  public synchronized AlignmentContext getAlignmentContext() {
-    return null; // by default the context is null
-  }
-
-      /**
+  /**
    * ProxyInfo to a NameNode. Includes its address.
    */
   public static class NNProxyInfo<T> extends ProxyInfo<T> {

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ObserverReadProxyProvider.java

@@ -113,7 +113,6 @@ public class ObserverReadProxyProvider<T extends ClientProtocol>
     }
   }
 
-  @Override
   public synchronized AlignmentContext getAlignmentContext() {
     return alignmentContext;
   }

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

@@ -94,11 +94,6 @@ public class TestStateAlignmentContextWithHA {
 
       AC_LIST.add(alignmentContext);
     }
-
-    @Override // AbstractNNFailoverProxyProvider
-    public synchronized ClientGSIContext getAlignmentContext() {
-      return this.alignmentContext;
-    }
   }
 
   static class SpyConfiguredContextProxyProvider<T>