diff --git a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/resolver/NamenodePriorityComparator.java b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/resolver/NamenodePriorityComparator.java
index fe82f29fbaa..e9724a3dee7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/resolver/NamenodePriorityComparator.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/resolver/NamenodePriorityComparator.java
@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdfs.server.federation.resolver;
 
+import java.io.Serializable;
 import java.util.Comparator;
 
 /**
@@ -31,7 +32,9 @@ import java.util.Comparator;
  * breaker, newest has priority. Expired NNs are excluded.
  */
 public class NamenodePriorityComparator
-    implements Comparator<FederationNamenodeContext> {
+    implements Comparator<FederationNamenodeContext>, Serializable {
+
+  private static final long serialVersionUID = 2304924292036293331L;
 
   @Override
   public int compare(FederationNamenodeContext o1,
diff --git a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RemoteMethod.java b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RemoteMethod.java
index cd57d457798..7978105584e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RemoteMethod.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RemoteMethod.java
@@ -76,7 +76,7 @@ public class RemoteMethod {
     }
 
     this.params = pParams;
-    this.types = pTypes;
+    this.types = Arrays.copyOf(pTypes, pTypes.length);
     this.methodName = method;
   }
 
@@ -111,7 +111,7 @@ public class RemoteMethod {
    * @return An array of calling types.
    */
   public Class<?>[] getTypes() {
-    return this.types;
+    return Arrays.copyOf(this.types, this.types.length);
   }
 
   /**