java字符串类型引用与字符类型引用的面试案例

public class Test3 {//4
	String string=new String("good");//2
	char[] ch={'a','b','c'};			//3
	public static void main(String[] args){
		Test3 test3=new Test3();//1
		test3.change(test3.string,test3.ch);//5
		System.out.println(test3.string+" and ");//8
		System.out.println(test3.ch);	//9
	}
	private void change(String string, char[] ch) {
		// TODO Auto-generated method stub
		string="test ok";//6
		ch[0]='g';//7
	}
}

good and 
gbc