Java交还两个变量的值

package com.binbin.test;

public class SwitchVariable {
	public static void main(String[] args) {
		Data data = new Data();
		data.m = 10;
		data.n = 20;
		System.out.println("m = " + data.m + ",n = " + data.n);

		System.out.println("++++++++++没有交换之前+++++++++");
		
		SwitchVariable sw = new SwitchVariable();
		sw.swap(data);
		System.out.println("m = " + data.m + ",n = " + data.n);

	}

	public void swap(Data d) {
		int tmp = d.m;
		d.m = d.n;
		d.n = tmp;
	}

}

class Data {
	int m;
	int n;
}