diff a/src/jdk.security.auth/share/classes/com/sun/security/auth/PrincipalComparator.java b/src/jdk.security.auth/share/classes/com/sun/security/auth/PrincipalComparator.java
--- a/src/jdk.security.auth/share/classes/com/sun/security/auth/PrincipalComparator.java
+++ b/src/jdk.security.auth/share/classes/com/sun/security/auth/PrincipalComparator.java
@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
@@ -53,10 +53,12 @@
 public interface PrincipalComparator {
     /**
      * Check if the specified {@code Subject} is implied by
      * this object.
      *
+     * @param  subject the subject to compare
+     *
      * @return true if the specified {@code Subject} is implied by
      *          this object, or false otherwise.
      */
     boolean implies(javax.security.auth.Subject subject);
 }
