/* a program to play with arraylists. */ package arraylistplay; import java.util.ArrayList; public class Primes { public static void main(String[] args) { ArrayList<Integer> primes = new ArrayList<>(); primes.add(2); primes.add(3); primes.add(5); primes.add(7); System.out.println("size of primes list = " + primes.size()); System.out.println("first prime = " + primes.get(0)); System.out.println("last prime = " + primes.get(3)); System.out.println("last prime = " + primes.get(primes.size()-1)); System.out.println("\nThe initial list..."); for (Integer prime : primes) { System.out.println(prime); } int temp = primes.get(0); primes.set(0,primes.get(primes.size()-1)); primes.set(primes.size()-1, temp); System.out.println("\nThe final list..."); for (Integer prime : primes) { System.out.println(prime); } } }