public class Ex2 {
    public void foo(int a, Integer b) {
        a = 2;
        b = 3;   // auto-boxing
    }
    public static void main(String[] args) {
        int x = 2;
        Integer y = 2; // auto-boxing
        Ex2 thing = new Ex2();
        thing.foo(x,y);
        System.out.println("x is "+x+"    y is "+y);
    }
}