src/java.base/share/classes/java/time/Year.java

@@ -145,10 +145,11 @@
     public static final int MAX_VALUE = 999_999_999;
 
     /**
      * Serialization version.
      */
+    @java.io.Serial
     private static final long serialVersionUID = -23038383694477807L;
     /**
      * Parser.
      */
     private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder()

@@ -1095,20 +1096,22 @@
      *  out.writeInt(year);
      * </pre>
      *
      * @return the instance of {@code Ser}, not null
      */
+    @java.io.Serial
     private Object writeReplace() {
         return new Ser(Ser.YEAR_TYPE, this);
     }
 
     /**
      * Defend against malicious streams.
      *
      * @param s the stream to read
      * @throws InvalidObjectException always
      */
+    @java.io.Serial
     private void readObject(ObjectInputStream s) throws InvalidObjectException {
         throw new InvalidObjectException("Deserialization via serialization delegate");
     }
 
     void writeExternal(DataOutput out) throws IOException {