Java中只有值传递，没有引用传递！

public static void changeInt(int a, int b) {
    a = 6;
    b = 7;
}

public static void changeStr(String a, String b) {
    a = "hello";
    b = "world";
}

static class Person {
    public String name = "Jack";
    public int age = 20;
}

public static void main(String[] args) {
    int intA = 1;
    int intB = 10;
    String stringA = "mm";
    String stringB = "boy";
    changeInt(intA, intB);
    changeStr(stringA, stringB);
    System.out.println("intA:" + intA + " intB:" + intB);
    System.out.println("stringA:" + stringA + " stringB:" + stringB);

    Person person = new Person();
    System.out.println("name:" + person.name + " age:" + person.age);

    person.name = "Rose";
    person.age = 18;
    System.out.println("new name:" + person.name + " age:" + person.age);
}                                                                                                              

输出结果

intA:1 intB:10
stringA:mm stringB:boy
name:Jack age:20
new name:Rose age:18