public static void main(String[] args) {
int x = 1;
int y = 2;
swap(x, y);
System.out.print("x=" + x);
System.out.print("y=" + y);
Integer a = new Integer(1);
Integer b = new Integer(2);
swap(a, b);
System.out.print("a=" + a.intValue());
System.out.print("b=" + b.intValue());