HDFS-10649. Remove unused PermissionStatus#applyUMask. Contributed by Chen Liang.

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

@@ -43,10 +43,6 @@ public class PermissionStatus implements Writable {
   public static PermissionStatus createImmutable(
       String user, String group, FsPermission permission) {
     return new PermissionStatus(user, group, permission) {
-      @Override
-      public PermissionStatus applyUMask(FsPermission umask) {
-        throw new UnsupportedOperationException();
-      }
       @Override
       public void readFields(DataInput in) throws IOException {
         throw new UnsupportedOperationException();
@@ -76,15 +72,6 @@ public class PermissionStatus implements Writable {
   /** Return permission */
   public FsPermission getPermission() {return permission;}
 
-  /**
-   * Apply umask.
-   * @see FsPermission#applyUMask(FsPermission)
-   */
-  public PermissionStatus applyUMask(FsPermission umask) {
-    permission = permission.applyUMask(umask);
-    return this;
-  }
-
   @Override
   public void readFields(DataInput in) throws IOException {
     username = Text.readString(in, Text.DEFAULT_MAX_LEN);