An example of how to reverse elements in the list.

ListReverse.java

package com.examples;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;

/**
 * This is utility class that contains an example of how to reverse elements in
 * the list. You shouldn't actually implement your own reverse utility - use
 * <code>Collections.reverse(List<?> list)</code> method instead.
 * 
 * @author Ivan Palianytsia
 */
public class ListReverse
{
	/**
	 * Reverses the list elements.
	 * 
	 * @param <T>
	 * Type of list elements.
	 * 
	 * @param list
	 * List to reverse elements in. Can't be null.
	 * 
	 * @throws IllegalArgumentException
	 * If the parameter given is null.
	 */
	public static <T> void reverse(List<T> list)
	{
		if (list == null)
		{
			throw new IllegalArgumentException(
					"Expected an object implementing list interface - null given.");
		}
		ListIterator<T> headIterator = list.listIterator();
		ListIterator<T> tailterator = list.listIterator(list.size());
		for (int i = 0; i < list.size() / 2; i++)
		{
			T headElement = headIterator.next();
			T tailElement = tailterator.previous();
			headIterator.set(tailElement);
			tailterator.set(headElement);
		}
	}

	public static void main(String[] args)
	{
		List<String> straight = new ArrayList<String>();
		straight.add("Ten");
		straight.add("Jack");
		straight.add("Queen");
		straight.add("King");
		straight.add("Ace");

		List<Integer> primes = new LinkedList<Integer>();
		primes.add(1);
		primes.add(3);
		primes.add(5);
		primes.add(7);
		primes.add(11);
		primes.add(13);

		System.out.println(straight);
		System.out.println(primes);

		reverse(straight);
		reverse(primes);

		System.out.println(straight);
		System.out.println(primes);

	}
}