src/java.base/share/classes/java/text/SimpleDateFormat.java

@@ -439,10 +439,11 @@
  */
 public class SimpleDateFormat extends DateFormat {
 
     // the official serial version ID which says cryptically
     // which version we're compatible with
+    @java.io.Serial
     static final long serialVersionUID = 4774881970558875024L;
 
     // the internal serial version which says which version was written
     // - 0 (default) for version up to JDK 1.1.3
     // - 1 for version from JDK 1.1.4, which includes a new field

@@ -2469,10 +2470,11 @@
      * After reading an object from the input stream, the format
      * pattern in the object is verified.
      *
      * @exception InvalidObjectException if the pattern is invalid
      */
+    @java.io.Serial
     private void readObject(ObjectInputStream stream)
                          throws IOException, ClassNotFoundException {
         stream.defaultReadObject();
 
         try {