java.lang.NullPointerException at java.util.TreeMap.rbDeleteFixup(TreeMap.java:810)

[Martin Schroeder]

Given this code:
-------
    public static void main (String [] argv) {
        TreeSet lpiSet, disallowedLpis;
        lpiSet = new TreeSet (new LongComparator ());
        disallowedLpis = new TreeSet (new LongComparator ());
        lpiSet.add (new Long (85));
        lpiSet.add (new Long (100));
            System.out.println (lpiSet);
            System.out.println (1);
        disallowedLpis.add (new Long (75));
        disallowedLpis.add (new Long (85));
        disallowedLpis.add (new Long (100));
            System.out.println (disallowedLpis);
            System.out.println (2);
        disallowedLpis.removeAll (lpiSet);
            System.out.println (3);
            System.out.println (disallowedLpis);
        }
-------
I get this crash:
-------
[85, 100]
1
[75, 85, 100]
2
java.lang.NullPointerException: 
        at java.util.TreeMap.rbDeleteFixup(TreeMap.java:810)
        at java.util.TreeMap.rbDelete(TreeMap.java:789)
        at java.util.TreeMap.remove(TreeMap.java:292)
        at java.util.TreeMap$TreeMapIterator.remove(TreeMap.java:1165)
        at java.util.AbstractCollection.removeAll(AbstractCollection.java:226)
        at de.artcomgmbh.ppdreader.PPD_UI_Frequency.main(PPD_UI_Frequency.java:657)
-------
$Id: TreeMap.java,v 1.3 1999/06/25 13:17:03 jochen Exp $

Before I dive into the implementation of java.util.TreeMap: Is
jochen or the author Jon Zeppieri reachable?

Thanks in advance
    Martin
-- 
                  Martin Schr�der, [EMAIL PROTECTED]
            ArtCom GmbH, Grazer Stra�e 8, D-28359 Bremen
           Voice +49 421 20419-44 / Fax +49 421 20419-10

import java.util.Comparator;

public class LongComparator implements Comparator {

    public int compare (Object o1, Object o2) {
        long thisVal = ((Long)o1).longValue ();
            long anotherVal = ((Long)o2).longValue ();

        return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1));

        } // public int compare

    }