src/java.base/share/classes/java/util/Properties.java

*** 140,149 ****
--- 140,150 ----
  public
  class Properties extends Hashtable<Object,Object> {
      /**
       * use serialVersionUID from JDK 1.1.X for interoperability
       */
+     @java.io.Serial
      private static final long serialVersionUID = 4112578634029874840L;
  
      private static final Unsafe UNSAFE = Unsafe.getUnsafe();
  
      /**