Name: avC70361 Date: 11/14/97



  If an instance of java.beans.PropertyChangeSupport, which has been added an
instance of PropertyChangeListener for a property name, has been serialized
into a stream and deserialized back the java.beans.PropertyChangeSupport.
hasListeners(String) method for that instance with the property name as the
parameter throws NullPointerException.

Here is the test demonstrating the bug:
------PropertyChangeSupportTest.java----------
import java.beans.*;
import java.io.*;

public class PropertyChangeSupportTest {

  public static void main(String args[]) {

    ObjectOutputStream ostream = null;
    ObjectInputStream istream = null;
    PropertyChangeSupport support = new PropertyChangeSupport(new String());
    support.addPropertyChangeListener(
      "prop",
      new PropertyChangeListener() {
        public void propertyChange(PropertyChangeEvent evt) {
        }
      }
    );
    support.hasListeners("prop");

    try {

      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      ostream = new ObjectOutputStream(baos);

      ostream.writeObject(support);
      ostream.flush();

      byte[] array = baos.toByteArray();
      baos.close();

      istream = new ObjectInputStream(
        new ByteArrayInputStream(array)
      );

      ((PropertyChangeSupport)istream.readObject()).hasListeners("prop");

    } catch(Exception e) {
      System.out.println("Exception raised : " + e);
    }
  }

}
---------------------
Test output
---------------------
#>java PropertyChangeSupportTest
Exception raised : java.lang.NullPointerException
---------------------

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