public class Test{
public static void main (String [] ABC){
StringBuffer a = new StringBuffer("A");
StringBuffer b = new StringBuffer("B");
operate(a,b);
System.out.println(a+","+b);
}
public static void operate (StringBuffer x,StringBuffer y){
x.append(y);
y=x;
}
}
输出:AB,B
x.append(y)使a为“AB”
而y=x语句没有改变b的内容,java的参数传递是传值。