package in.bench.resources.java.collections;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;

public class DifferentWaysToIterateArrayList {

	public static void main(String[] args) {

		// creating ArrayList object of type String
		ArrayList<String> al = new ArrayList<String>();

		// adding elements to ArrayList object
		al.add("Sundar Pichai");
		al.add("Satya Nadella");
		al.add("Shiv Nadar");
		al.add("Shantanu Narayen");
		al.add("Sundar Pichai"); // duplicate object
		al.add("Francisco D’Souza");
		al.add(null); // null is allowed

		// Way 1: Iterating using for-loop
		System.out.println("Way 1: Iterating using for-loop\n");
		for(int index = 0; index < al.size(); index++) {
			System.out.println(al.get(index));
		}

		// Way 2: Iterating using enhanced for-loop
		System.out.println("\n\nWay 2: Iterating using "
				+ "enhanced for-loop\n");
		for(String str : al) {
			System.out.println(str);
		}

		// Way 3: Iterating using Iterator of Collection interface
		System.out.println("\n\nWay 3: Iterating using "
				+ "Iterator of Collection interface\n");
		Iterator<String> itr = al.iterator();
		while(itr.hasNext()) {
			System.out.println(itr.next());
		}

		// Way 4: Iterating using ListIterator of List interface
		System.out.println("\n\nWay 4.A: Iterating using ListIterator of "
				+ "List interface in FORWARD direction\n");
		ListIterator<String> lstItr = al.listIterator();
		while(lstItr.hasNext()) {
			System.out.println(lstItr.next());
		}

		System.out.println("\n\nWay 4.B: Iterating using ListIterator of "
				+ "List interface in BACKWARD direction\n");
		while(lstItr.hasPrevious()) {
			System.out.println(lstItr.previous());
		}
	}
}

Way 1: Iterating using for-loop

Sundar Pichai
Satya Nadella
Shiv Nadar
Shantanu Narayen
Sundar Pichai
Francisco D’Souza
null

Way 2: Iterating using enhanced for-loop

Sundar Pichai
Satya Nadella
Shiv Nadar
Shantanu Narayen
Sundar Pichai
Francisco D’Souza
null

Way 3: Iterating using Iterator of Collection interface

Sundar Pichai
Satya Nadella
Shiv Nadar
Shantanu Narayen
Sundar Pichai
Francisco D’Souza
null

Way 4.A: Iterating using ListIterator of List interface in FORWARD dir

Sundar Pichai
Satya Nadella
Shiv Nadar
Shantanu Narayen
Sundar Pichai
Francisco D’Souza
null

Way 4.B: Iterating using ListIterator of List interface in BACKWARD dir

null
Francisco D’Souza
Sundar Pichai
Shantanu Narayen
Shiv Nadar
Satya Nadella
Sundar Pichai