JAVA引用传递

public class TestAppend {        public static void change(StringBuffer x,StringBuffer y)        {                x.append(y);           //x-->AB        x = y;         //x指向y-->B                System.out.println(x);//x-->B                System.out.println(y);//y-->B        }        public static void main(String [] args)        {                StringBuffer a = new StringBuffer("A");//a-->A                StringBuffer b = new StringBuffer("B");//b-->B                change(a,b);                System.out.println(a);//a-->AB                System.out.println(b);//b-->B        }}