🚀 go-pugleaf

hi all,

I'm trying to do the following in Java.
I have a class that contains an ArrayList.
At certain points in the program I want to mark a position in the ArrayList.

e.g. If I had "A" and "B" then 'mark' and then add "C" and "D"
Then, when I say, 'showFrom()" I should only get to see "C" and "D".
I tried to use an Iterator to do this, but with no succes.
I get the following

Exception in thread "main" java.util.ConcurrentModificationException
         at
java.util.AbstractList$Itr.checkForComodification(AbstractList.java:444)
         at java.util.AbstractList$Itr.next(AbstractList.java:417)
         at IteratorTest.moveIterator(IteratorTest.java:27)
         at IteratorTest.main(IteratorTest.java:41)

The code I tried is the following.

import java.util.*;

public class IteratorTest {
         private ArrayList a;
         private Iterator i;

         public IteratorTest() {
                 a = new ArrayList();
                 i = a.iterator();
         }

         public String toString() {
                 return a.toString();
         }

         public void add(Object o) {
                 a.add(o);
         }

         public void showAll() {
                 Iterator ii = a.iterator();
                 while (ii.hasNext())
                         System.out.print(ii.next() + " ");
         }
         // this should reset the mark
         public void moveIterator() {
                 while (i.hasNext()) i.next();
         }

         public void showFrom() {
                 Iterator ii = i;
                 while (ii.hasNext()) System.out.print(ii.next());
         }

         public static void main(String []args) {
              IteratorTest it = new IteratorTest();
              it.add("A");
              it.add("B");
              it.showAll();
              System.out.println("");
              it.moveIterator();
              it.add("C");
              it.add("D");
              it.showFrom(); // here, I hope to see only C and D
              System.out.println();
         }

}

Thanks for any suggestion on how to solve this problem.

Stino.