如何同时打印和删除迭代器中的元素？

Question

I was going through collections in Java and came across some iterator examples. I am giving the code below

public class iteratorexample {

    public static void main(String[] args) {

        String removeE="New York";
        List<String> thelist = new ArrayList<String>();

        thelist.add("Dallas");
        thelist.add("Richmond");
        thelist.add("Atlanta");
        thelist.add("New York");
        thelist.add("Birmingham");
        System.out.print(thelist);
        System.out.println();
        Iterator<String> itr= thelist.iterator();
        /*while(itr.hasNext()){

            System.out.print(" " +itr.next()+" ");
        } */
        **while(itr.hasNext()){
            String remo=(String)itr.next();
            if(remo.equals(removeE)){
                itr.remove();

            }

        }**

        System.out.println();
        System.out.println("After removing: ");
        System.out.println(thelist);

        }
        }

Above Code give output 
[Dallas, Richmond, Atlanta, New York, Birmingham]

After removing: 
[Dallas, Richmond, Atlanta, Birmingham]

Why?

If I use both the while loops the iterator does not remove the element from the list, why? Can you help me out.

public static void main(String[] args) {

        String removeE="New York";
        List<String> thelist = new ArrayList<String>();

        thelist.add("Dallas");
        thelist.add("Richmond");
        thelist.add("Atlanta");
        thelist.add("New York");
        thelist.add("Birmingham");
        System.out.print(thelist);
        System.out.println();
        Iterator<String> itr= thelist.iterator();
        while(itr.hasNext()){

            System.out.print(" " +itr.next()+" ");
        } 
        while(itr.hasNext()){
            String remo=(String)itr.next();
            if(remo.equals(removeE)){
                itr.remove();

            }

        }

        System.out.println();
        System.out.println("After removing: ");
        System.out.println(thelist);

        }
        }

Above code gives output

[Dallas, Richmond, Atlanta, New York, Birmingham]
 Dallas  Richmond  Atlanta  New York  Birmingham 
After removing: 
[Dallas, Richmond, Atlanta, New York, Birmingham]   

Answer 1

If I use both the while loops the iterator does not remove the element from the list, why?

Because when the first loop is complete, the iterator's hasNext is false. So the code never enters the second loop at all.

To loop a second time, you'd have to get a new iterator.

In collections that support it, you could both print and remove in one loop by using the remove method of the iterator.

while(itr.hasNext()){
    String remo=(String)itr.next();
    System.out.print(" " +remo+" ");
    if(remo.equals(removeE)){
        itr.remove();
    }
}

Answer 2

You are doing:

while(itr.hasNext()){
   System.out.print(" " +itr.next()+" ");
} 
while(itr.hasNext()){

so after first while loop your iterator will be completed.