1 package arraylistplay; 2 3 import java.util.ArrayList; 4 5 public class Primes { 6 public static void main(String[] args) { 7 ArrayList<Integer> primes = new ArrayList<>(); 8 primes.add(2); 9 primes.add(3); 10 primes.add(5); 11 primes.add(7); 12 System.out.println("size of primes list = " + primes.size()); 13 System.out.println("first prime = " + primes.get(0)); 14 System.out.println("last prime = " + primes.get(3)); 15 System.out.println("last prime = " + primes.get(primes.size()-1)); 16 17 System.out.println("\nThe initial list ..."); 18 for (Integer prime : primes ){ 19 System.out.println(prime); 20 } 21 int temp = primes.get(0); 22 primes.set(0, primes.get(primes.size()-1)); 23 primes.set(primes.size()-1,temp); 24 25 System.out.println("\nThe final array ..."); 26 for ( Integer prime : primes ) { 27 System.out.println(prime); 28 } 29 } 30 } 31 32