对象传递为引用

package Test;

public class TestA
{
	String a = null;

	public String getA()
	{
		return a;
	}

	public void setA(String a)
	{
		this.a = a;
	}
	
}

package Test;


public class TestB
{

	public static void main(String args[])
	{
		TestA a = new TestA();
		a.setA("xxx");
		System.out.println("1 " + a.getA());
		
		
		TestB b = new TestB();
		b.ooA(a);
		System.out.println("3 " + a.getA());
	}

	public void ooA(TestA a)
	{
		a.setA("ooo");
		System.out.println("2 " + a.getA());
	}
}

1 xxx
2 ooo
3 ooo

原来之前抄过一篇相同内容的笔记。。。
http://xserver.iteye.com/blog/623409
忘记留原文地址了，抱歉。。。