src/java.base/share/classes/com/sun/java/util/jar/pack/ClassReader.java

@@ -603,10 +603,11 @@
         cls.innerClasses = ics;  // set directly; do not use setInnerClasses.
         // (Later, ics may be transferred to the pkg.)
     }
 
     static class ClassFormatException extends IOException {
+        @java.io.Serial
         private static final long serialVersionUID = -3564121733989501833L;
 
         public ClassFormatException(String message) {
             super(message);
         }