java.util.ConCurrentModificationException

I tried to execute following code

ListIterator iterator = i.listIterator();
while(iterator.hasNext()) {
      System.out.println(iterator.next());
      Object obj=((Integer)iterator.next()).intValue();
      if(obj.equals(i.get(1))) {
           i.add(10);
      }
}

ant it throws following exception

Exception in thread "main" java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)

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