Question

Stack<String> sk = new Stack<String>();

sk.push("Hello");
sk.push("Hello1");
sk.push("Hello2");

There are two ways i am iterating this Stack Object.

for(String s : sk){
   System.out.println("The Values of String in SK" +sk);
}

// Way two..

Iterator<String> it=sk.iterator();
    while(it.hasNext())
    {
        String iValue=(String)it.next();
        System.out.println("Iterator value :"+iValue);
    }

1. What is the difference between these two?
2. Any Advantage if i choose one among them?
3. Which is the preferred way of iterating?

Answer 1

1. What is the difference between these two?

Not much. The for-each loop construct actually relies on the iterator behind the curtains.

Further reading:

• The For-Each Loop, official documentation / tutorial

2. Any Advantage if i choose one among them?

Mostly readability I would assume.

(If you need to access the iterator.remove() method, then obviously you would need to go with the explicit Iterator approach.) However, keep in mind that it’s an optional operation and may not be supported by the underlying Stack implementation you’re using.

Besides, the point of a Stack structure is that you don’t remove elements in the middle.

3. Which is the preferred way of iterating?

Use the for-each approach, if that works for you.