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    
9            primes.add(2);
10           primes.add(3);
11           primes.add(5);
12           primes.add(7);
13   
14           System.out.println("length of primes list = " + primes.size());
15           System.out.println("firrst prime = " + primes.get(0));
16           System.out.println("last prime = " + primes.get(3));
17           System.out.println("last prime = " + primes.get(primes.size()-1));
18   
19           System.out.println("The initial list ...");
20           for ( Integer prime : primes){
21               System.out.println(prime);
22           }
23   
24           int temp = primes.get(0);
25           primes.set(0, primes.get(primes.size()-1));
26           primes.set(primes.size()-1,temp);
27   
28           System.out.println("the final list ...");
29           for ( Integer prime : primes){
30               System.out.println(prime);
31           }
32       }
33   }
34