Swapping numbers program

public class swap1
{
    public static void main()
    {
        int temp;
        int a=3;
        int b=9;
        temp=a;
        a=b;
        b=temp;
        System.out.println("After swapping, a="+a);
        System.out.println("After swapping, b="+b);
    }

public class swap2
{
    public static void main()
    {
        int a=3;
        int b=9;
        a=a+b;
        b=a-b;
        a=a-b;
       System.out.println("After swapping, a="+a);
       System.out.println("After swapping, b="+b);
    }