这次结果为何是goodandgbc

Question

public class MyTest {
    String str = new String("good");
    char[] ch = { 'a', 'b', 'c' };

    public static void main(String[] args) {
        MyTest ex = new MyTest();
        ex.change(ex.str, ex.ch);
        System.out.print(ex.str + "and");
        System.out.print(ex.ch);
    }

    public void change(String str, char ch[]) {
        str = "test ok";
        ch[0] = 'g';
    }
}

Answer 1

调用change方法，str只是改了局部变量的内容，不影响外部值，因此还是good
数组改变了同一个引用地址的内容，所以为gbc