SYNOPSIS
--------
Incompatible changes made to JDK 7 Serializable Swing classes

OPERATING SYSTEM
----------------
All

FULL JDK VERSION
----------------
JDK 7

PROBLEM DESCRIPTION from LICENSEE
---------------------------------
I'm not sure exactly when the changes occurred, but the serialized form of the following classes in recent JDK 7 builds are not compatible with prior versions of Java:

    javax.swing.text.html.parser.ParserDelegator
    javax.swing.LayoutComparator

These classes need to be modified such that their SUIDs match previous releases (if that is possible/appropriate), or they need to be declared as not compatible between releases in the API documentation, as is the case for some other serializable Swing classes. For example, the documentation for javax.swing.border.BevelBorder states:

    Warning: Serialized objects of this class will not be compatible
    with future Swing releases. The current serialization support is
    appropriate for short term storage or RMI between applications
    running the same version of Swing.

REPRODUCTION INSTRUCTIONS
-------------------------
Compile and run the attached testcase against the two classes highlighted above, on Java 6 and JDK 7. For example:

    java GetSUID javax.swing.text.html.parser.ParserDelegator
    2393192570582355838 (calculated)

 The results for the two classes highlighted above are:

    javax.swing.text.html.parser.ParserDelegator
      Java 6 (6u24): 2393192570582355838
       JDK 7 (b134): 1832828210669556215

    javax.swing.LayoutComparator
      Java 6 (6u24): -4870018609087598032
       JDK 7 (b134): 8239258917856577386

TESTCASE
--------
import java.lang.reflect.*;

public class GetSUID {
    public static void main (String args[]) throws Exception {
        if (args.length != 1) {
            System.out.println("Usage: java GetSUID [class name]");
            System.exit(1);
        }

        // Get the target Class
        Class targetClass = Class.forName(args[0]);
     
        // Get the explicit SUID field (if it exists)
        try {
            Field suid = targetClass.getDeclaredField("serialVersionUID");
            suid.setAccessible(true);
            System.out.println(suid.getLong(null) + " (declared)");
            System.exit(0);
        } catch (NoSuchFieldException e) {
            // SUID not declared. Catch Exception and move on...
        }
       
        // Get the computed SUID
        Class oscClass = Class.forName("com.sun.corba.se.impl.io.ObjectStreamClass");
        Method computeMethod = oscClass.getDeclaredMethod("_computeSerialVersionUID", new Class[] { Class.class });
        computeMethod.setAccessible(true);
        Long suid = (Long)computeMethod.invoke(null, new Object[] { targetClass });
        System.out.println(suid.longValue() + " (calculated)");
    }
}
Should this bug be p3? Perhaps this bug should be lowered according to Impact, liklihood and workaround guideline.