src/java.base/share/classes/java/util/regex/Pattern.java

@@ -933,10 +933,11 @@
      * and the flags, which are all that is needed to recompile the pattern
      * when it is deserialized.
      */
 
     /** use serialVersionUID from Merlin b59 for interoperability */
+    @java.io.Serial
     private static final long serialVersionUID = 5073258162644648461L;
 
     /**
      * The original regular-expression pattern string.
      *

@@ -1374,10 +1375,11 @@
 
     /**
      * Recompile the Pattern instance from a stream.  The original pattern
      * string is read in and the object tree is recompiled from it.
      */
+    @java.io.Serial
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
 
         // Read in all fields
         s.defaultReadObject();