src/java.base/share/classes/java/io/File.java

*** 2215,2224 ****
--- 2215,2225 ----
       * The separator character is saved also so it can be replaced
       * in case the path is reconstituted on a different host type.
       *
       * @serialData  Default fields followed by separator character.
       */
+     @java.io.Serial
      private synchronized void writeObject(java.io.ObjectOutputStream s)
          throws IOException
      {
          s.defaultWriteObject();
          s.writeChar(separatorChar); // Add the separator character
*** 2228,2237 ****
--- 2229,2239 ----
       * readObject is called to restore this filename.
       * The original separator character is read.  If it is different
       * than the separator character on this system, then the old separator
       * is replaced by the local separator.
       */
+     @java.io.Serial
      private synchronized void readObject(java.io.ObjectInputStream s)
           throws IOException, ClassNotFoundException
      {
          ObjectInputStream.GetField fields = s.readFields();
          String pathField = (String)fields.get("path", null);
*** 2249,2258 ****
--- 2251,2261 ----
              = UNSAFE.objectFieldOffset(File.class, "path");
      private static final long PREFIX_LENGTH_OFFSET
              = UNSAFE.objectFieldOffset(File.class, "prefixLength");
  
      /** use serialVersionUID from JDK 1.0.2 for interoperability */
+     @java.io.Serial
      private static final long serialVersionUID = 301077366599181567L;
  
      // -- Integration with java.nio.file --
  
      private transient volatile Path filePath;