引用地址的变化

 1 public static void main(String[] args) {
 2       StringBuffer a=new StringBuffer("A");
 3       StringBuffer b=new StringBuffer("B");
 4       operator(a,b);   // 1
 5       System.out.println(a+","+b);  // 3 
 6    }
 7    public static void operator(StringBuffer x,StringBuffer y){
 8       x.append(y);
 9       y=x;  //当 y = x时，你是改变了 y 的引用指向     2
10    }
11 }
12 
13 
14 //1. a = A   b = B    a:内存1   b:内存2
15 //2. a = AB  b = AB   a:内存1   b:内存1
16 //3. a = AB  b = B    a:内存1   b:内存2
往事如烟,余生有我.