src/java.base/share/classes/sun/net/www/protocol/http/AuthenticationInfo.java

@@ -51,10 +51,11 @@
 //      policy in HttpURLConnection.  A failure on baz.foo.com shouldn't
 //      uncache foo.com!
 
 public abstract class AuthenticationInfo extends AuthCacheValue implements Cloneable {
 
+    @java.io.Serial
     static final long serialVersionUID = -2588378268010453259L;
 
     // Constants saying what kind of authroization this is.  This determines
     // the namespace in the hash table lookup.
     public static final char SERVER_AUTHENTICATION = 's';

@@ -496,10 +497,11 @@
         }
     }
 
     String s1, s2;  /* used for serialization of pw */
 
+    @java.io.Serial
     private synchronized void readObject(ObjectInputStream s)
         throws IOException, ClassNotFoundException
     {
         s.defaultReadObject ();
         pw = new PasswordAuthentication (s1, s2.toCharArray());

@@ -507,10 +509,11 @@
         if (authenticatorKey == null) {
             authenticatorKey = AuthenticatorKeys.DEFAULT;
         }
     }
 
+    @java.io.Serial
     private synchronized void writeObject(java.io.ObjectOutputStream s)
         throws IOException
     {
         Objects.requireNonNull(authenticatorKey);
         s1 = pw.getUserName();