List.removeAll

[gpatynek]

Hello, why this code is incorrect?

import java.util.*;

public class OperatingLists {
public static void main(String[] args){
List<OperatingLists> list = new ArrayList<OperatingLists>();
list.add(new OperatingLists());
List<OperatingLists> subList = list.subList(0, 1);
list.removeAll(subList);
}
}

The code is:
I create Generic List containing OperatingLists object.
I create sub-List of List containing one element.
i compile and run:

Exception in thread "main" java.util.ConcurrentModificationException
at java.util.SubList.checkForComodification(AbstractList.java:752)
at java.util.SubList.listIterator(AbstractList.java:682)
at java.util.AbstractList.listIterator(AbstractList.java:284)
at java.util.SubList.iterator(AbstractList.java:678)
at java.util.AbstractCollection.toString(AbstractCollection.java:414)
at java.lang.String.valueOf(String.java:2827)
at java.lang.StringBuilder.append(StringBuilder.java:115)
at holding.OperatingLists.main(OperatingLists.java:23)
Java Result: 1

line 23 is line with removeAll method.

Anyone can explain?