src/java.base/share/classes/java/lang/Throwable.java

@@ -112,10 +112,11 @@
  * @jls 11.2 Compile-Time Checking of Exceptions
  * @since 1.0
  */
 public class Throwable implements Serializable {
     /** use serialVersionUID from JDK 1.0.2 for interoperability */
+    @java.io.Serial
     private static final long serialVersionUID = -3042686055658047285L;
 
     /**
      * The JVM saves some indication of the stack backtrace in this slot.
      */

@@ -899,10 +900,11 @@
      *
      * Note that there are no constraints on the value the {@code
      * cause} field can hold; both {@code null} and {@code this} are
      * valid values for the field.
      */
+    @java.io.Serial
     private void readObject(ObjectInputStream s)
         throws IOException, ClassNotFoundException {
         s.defaultReadObject();     // read in all fields
 
         // Set suppressed exceptions and stack trace elements fields

@@ -987,10 +989,11 @@
      *
      * A {@code null} stack trace field is represented in the serial
      * form as a one-element array whose element is equal to {@code
      * new StackTraceElement("", "", null, Integer.MIN_VALUE)}.
      */
+    @java.io.Serial
     private synchronized void writeObject(ObjectOutputStream s)
         throws IOException {
         // Ensure that the stackTrace field is initialized to a
         // non-null value, if appropriate.  As of JDK 7, a null stack
         // trace field is a valid value indicating the stack trace