import java.lang.reflect.Field;

public class Test {

    public static void main(String[] args) {

        Integer a=1000;

        Integer b=890;

        System.out.println("a="+a+",b="+b);

        swap(a,b);

        System.out.println("a="+a+",b="+b);

    }

    private static void swap(Integer a,Integer b){

        try {

            int tempA=b.intValue();

            int tempB=a.intValue();

            Field field=Integer.class.getDeclaredField("value");

            field.setAccessible(true);

            field.setInt(a, tempA);

            field.setInt(b, tempB);

            System.out.println("a="+tempA+",b="+tempB);

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}