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Thread: Reference type

  1. #1
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    Default Reference type

    class Person {
     
        int value;
     
        Person() {
            value=0;
        }
     
     
    }
     
     
    class HelloWorld {
     
        public static void main(String[] args) {
            System.out.println("Hello World");
     
     
            Person p=new Person();
            System.out.println(p.value);
     
            //setValue(p,100);
            HelloWorld h=new HelloWorld();
            h.setValue(p,100);
     
            System.out.println(p.value);
     
     
        }
     
        static void setValue(Person p, int v) {
     
            p.value=v;
     
        }
    }

    p.value has changed from 0 to 100.


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Reference type

    Did you have a question?
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
    Member andbin's Avatar
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    Default Re: Reference type

    Quote Originally Posted by gunitinug View Post
    p.value has changed from 0 to 100.
    Yes. Was this your question or doubt?
    setValue receives a copy of the reference to the Person object instantiated in main. This means that setValue cannot change the value of the 'p' variable in the main ..... but can change the state of the object, if it has accessible instance variables or any "mutator" methods.
    Andrea, www.andbin.net SCJP 5 (91%) SCWCD 5 (94%)

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