diff a/src/java.smartcardio/share/classes/javax/smartcardio/ResponseAPDU.java b/src/java.smartcardio/share/classes/javax/smartcardio/ResponseAPDU.java
--- a/src/java.smartcardio/share/classes/javax/smartcardio/ResponseAPDU.java
+++ b/src/java.smartcardio/share/classes/javax/smartcardio/ResponseAPDU.java
@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 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
@@ -24,10 +24,11 @@
  */
 
 package javax.smartcardio;
 
 import java.util.Arrays;
+import java.io.IOException;
 
 /**
  * A response APDU as defined in ISO/IEC 7816-4. It consists of a conditional
  * body and a two byte trailer.
  * This class does not attempt to verify that the APDU encodes a semantically
@@ -174,12 +175,19 @@
      */
     public int hashCode() {
         return Arrays.hashCode(apdu);
     }
 
+    /**
+     * Restores the state of this object from the stream.
+     *
+     * @param  in the {@code ObjectInputStream} from which data is read
+     * @throws IOException if an I/O error occurs
+     * @throws ClassNotFoundException if a serialized class cannot be loaded
+     */
     private void readObject(java.io.ObjectInputStream in)
-            throws java.io.IOException, ClassNotFoundException {
+            throws IOException, ClassNotFoundException {
         apdu = (byte[])in.readUnshared();
         check(apdu);
     }
 
 }
