What is the difference between java.util.Iterator and java.util.ListIterator?

Iterator : Enables you to traverse through a collection in the forward direction only, for obtaining or removing elements.

ListIterator : extends Iterator, and allows bidirectional traversal of list and also allows the modification of elements.

Example:


import java.util.*;


public class Demo {


   public static void main(String args[]) {
      ArrayList al = new ArrayList();
      al.add("A");
      al.add("B");
      al.add("C");
      al.add("D");
      al.add("E");
      al.add("F");


      //iterator 
      System.out.print("Original contents of al: ");
      Iterator itr = al.iterator();
      while(itr.hasNext()) {
         Object element = itr.next();
         System.out.print(element + " ");
      }
      System.out.println();
      
 // listIterator modifying objects
      ListIterator litr = al.listIterator();
      while(litr.hasNext()) {
         Object element = litr.next();
         litr.set(element + "-");
      }


      System.out.print("Modified contents of al: ");


      itr = al.iterator();
      while(itr.hasNext()) {
         Object element = itr.next();
         System.out.print(element + " ");
      }
      System.out.println();


      // Now, display the list backwards
      System.out.print("Modified list backwards: ");
      while(litr.hasPrevious()) {
         Object element = litr.previous();
         System.out.print(element + " ");
       }
       System.out.println();
    }
}


output :


Original contents of al: A B C D E F
Modified contents of al: A- B- C- D- E- F-
Modified list backwards: F- E- D- C- B- A-