Java的参数传递

import java.util.Arrays;
public class Demmo{
    private String str="1234";
    private char[] chars={'a','b','c'};
    public static void main(String[] args){
        Demmo demmo=new Demmo();
        System.out.println(demmo.str+"  "+ Arrays.toString(demmo.chars));
        exchange(demmo.str,demmo.chars);
        System.out.println(demmo.str+"  "+ Arrays.toString(demmo.chars));
    }
    public static void exchange(String str,char[] chars){
        str="5678";
        chars[2]='b';
    }
}