Enhanced for loop and iterator in Java

Question

I have a class MyList that implements Iterable interface. And here is a toString() method from one of my classes:

public String toString() {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < 4; i++) {
        // First example using iterator
        for (Iterator<Integer> itr = array[i].iterator(); itr.hasNext();) {
            sb.append(itr.next() + " ");
        }
        // And the same result using enhanced for loop
        for (int val : array[i]) {
            sb.append(val + " ");
        }
    }
    return sb.toString();
}

This loop iterates over the nodes in my list:

for (int val : array[i]) {
    sb.append(val + " ");
}

How does this for loop uses the iterator?

Answer 1

Because your class (MyList) implements Iterable. So internally it will call your iterator() method and then with the use of hasNext() and next() methods of ListIterator it will iterate in for loop.

Refer : Using Enhanced For-Loops with Your Classes