TreeMap.DescendingKeyIterator 'remove' confuses iterator position

FULL PRODUCT VERSION :
Java HotSpot(TM) 64-Bit Server VM (build 23.25-b01, mixed mode)


A DESCRIPTION OF THE PROBLEM :
The implementation of 'remove' in PrivateEntryIterator in TreeMap.java does not work correctly when it is a descending iterator.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Put at least 3 elements into a TreeMap.
2. Get a descending iterator for a TreeMap's KeySet.
3. Iterate through the elements, and remove the second one.

The iterator position is now wrong. (See the test case below for source code.)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NavigableMap;
import java.util.TreeMap;

public class TreeMapIteratorBug {
  public static void main(String [] argv) throws Exception {
    NavigableMap<String, Object> map = new TreeMap<String, Object>();
    map.put("a", 1);
    map.put("b", 1);
    map.put("c", 1);

    List<String> keys = new ArrayList<String>();
    keys.addAll(map.descendingMap().keySet());

    Iterator<String> iterator = map.navigableKeySet().descendingIterator();
    for (int i = 0; i < 3; i++) {
      String key = iterator.next();
      if (!key.equals(keys.get(i))) {
        throw new Exception("bug");
      }
      if (i == 1) {
        iterator.remove();
      }
    }
  }
}

---------- END SOURCE ----------