Serialization for java.awt.ScrollPane causes compatibility problem

Name: ooR10001 Date: 04/13/2001


Serialization for java.awt.ScrollPane causes compatibility problem because
instance of SrollPane, serialized under jdk version older than 1.4, incorrectly
deserialized under jdk1.4.

Following minimized test shows the bug:

This code compiled and executed under jdk1.3.
Result is creating 'test.ser' file and print the value of scrollbarDisplayPolicy
----------------------------
import java.awt.ScrollPane;

public class t {

  public static void main(String[] args) {
     try {
          java.io.FileOutputStream fos =
                  new java.io.FileOutputStream("test.ser");
          java.io.ObjectOutputStream oos = new java.io.ObjectOutputStream(fos);
          ScrollPane sp = new ScrollPane(ScrollPane.SCROLLBARS_ALWAYS);
          System.out.println("Serialized display policy is: "
                             + sp.getScrollbarDisplayPolicy());
          oos.writeObject(sp);
          oos.close();
          fos.close();
      } catch (java.io.IOException e) {
          e.printStackTrace();
      }
  }
}
----------------------------

Output:
-------------
Serialized display policy is: 1
-------------

This code compiled under jdk1.4.
Result is deserialising ScrollPane instance from 'test.ser' file
and print the value of deserialized scrollbarDisplayPolicy.

----------------------------
import java.awt.ScrollPane;

public class t {

  public static void main(String[] args) {
      try {
          java.io.FileInputStream fis =
                  new java.io.FileInputStream("test.ser");
          java.io.ObjectInputStream ois = new java.io.ObjectInputStream(fis);
          ScrollPane x = (ScrollPane)ois.readObject();
          System.out.println("Deserialized display policy is: "
                             + x.getScrollbarDisplayPolicy());
          ois.close();
          fis.close();
      } catch (ClassNotFoundException e) {
          e.printStackTrace();
      } catch (java.io.IOException e) {
          e.printStackTrace();
}
      }
}
----------------------------

Output:
---------------
Deserialized display policy is: 0
---------------

This is a crossversion compatibility problem. It needs to be fixed.

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