diff a/src/java.base/share/classes/java/security/GuardedObject.java b/src/java.base/share/classes/java/security/GuardedObject.java
--- a/src/java.base/share/classes/java/security/GuardedObject.java
+++ b/src/java.base/share/classes/java/security/GuardedObject.java
@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -23,10 +23,12 @@
  * questions.
  */
 
 package java.security;
 
+import java.io.IOException;
+
 /**
  * A GuardedObject is an object that is used to protect access to
  * another object.
  *
  * <p>A GuardedObject encapsulates a target object and a Guard object,
@@ -50,14 +52,21 @@
 public class GuardedObject implements java.io.Serializable {
 
     @java.io.Serial
     private static final long serialVersionUID = -5240450096227834308L;
 
+    /**
+     * The object we are guarding.
+     */
     @SuppressWarnings("serial") // Not statically typed as Serializable
-    private Object object; // the object we are guarding
+    private Object object;
+
+    /**
+     * The guard object.
+     */
     @SuppressWarnings("serial") // Not statically typed as Serializable
-    private Guard guard;   // the guard
+    private Guard guard;
 
     /**
      * Constructs a GuardedObject using the specified object and guard.
      * If the Guard object is null, then no restrictions will
      * be placed on who can access the object.
@@ -92,14 +101,17 @@
     }
 
     /**
      * Writes this object out to a stream (i.e., serializes it).
      * We check the guard if there is one.
+     *
+     * @param  oos the {@code ObjectOutputStream} to which data is written
+     * @throws IOException if an I/O error occurs
      */
     @java.io.Serial
     private void writeObject(java.io.ObjectOutputStream oos)
-        throws java.io.IOException
+        throws IOException
     {
         if (guard != null)
             guard.checkGuard(object);
 
         oos.defaultWriteObject();
