Java Integer Swap Exercise

package swap2randomnumbers;

import java.util.Random;
import java.util.Scanner;

final class Pair {

    private Integer a, b;
    private final Random random;

    public Pair(Random random) {
        this.random = random;
        this.gen();
    }

    public void gen() {
        this.genA();
        this.genB();
    }

    public Integer getA() {
        return a;
    }

    public void setA(final Integer a) {
        this.a = a;
    }

    public void genA() {
        this.a = this.random.nextInt();
    }

    public Integer getB() {
        return b;
    }

    public void genB() {
        this.b = this.random.nextInt();
    }

    public void setB(final Integer b) {
        this.b = b;
    }
}

/**
 *
 * @author Aidan
 */
public class Swap2RandomNumbers {

    static {
        renew_input();
        renew_random();
    }

    private static Random random;
    private static Scanner input;

    private static void renew_input() {
        input = new Scanner(System.in);
    }

    private static void renew_random() {
        random = new Random();
    }

    public static void main(String[] args) {
        Pair obj = new Pair(random);
        output(obj);
        //
        swap1(obj);
        output(obj);
        //
        obj.gen();
        output(obj);
        swap2(obj);
        output(obj);
        //
        obj.gen();
        output(obj);
        swap3(obj);
        output(obj);
    }

    private static void swap1(Pair x) {
        Integer tmp = x.getA();
        x.setA(x.getB());
        x.setB(tmp);
    }

    private static void swap2(Pair x) {
        /*
         a = a + b;
         b = a - b;
         a = a - b;
         */
        x.setA(x.getA() + x.getB());
        x.setB(x.getA() - x.getB());
        x.setA(x.getA() - x.getB());
    }

    private static void swap3(Pair x) {
        /*
         a = a ^ b;
         b = a ^ b;
         a = a ^ b;
         */
        x.setA(x.getA() ^ x.getB());
        x.setB(x.getA() ^ x.getB());
        x.setA(x.getA() ^ x.getB());
    }

    private static void output(Pair obj) {
        System.out.println("The pair is " + obj.getA() + " and " + obj.getB() + '.');
        System.out.flush();
    }

}