CODEWITHSUNDEEP
javaoopobjectmethodsinstance
Shane
Shane

Reputation: 115

Regarding Object/Class Instances in Java

Consider the scenario below:

public class ClassA {

    private Main main;
    Object obj = new Object;

    public void setMain(Main main) {
        this.main = main;
    }
    methodA() {  //called first
        obj.someFunction();
        main.someFunction();
    }
    methodB() {  //called second
        obj.someOtherFunction();
    }
}

Would methodB be using the same instance of "obj" as methodA? If not, how could the code be altered to make it so?

I apologize for such a basic question, but it is a concept that has been unclear for me since I started learning java, even after countless searches online.

Upvotes: 0

Views: 46

Answers (3)

Alexander
Alexander

Reputation: 63167

If you're test case is:

ClassA objectA = new ClassA(new Main());
objectA.methodA();
objectA.methodB();

with nothing in between the calls to methodA() then methodB() that would change the value of the obj instance variable, then yes, they would both use the same obj instance.

Upvotes: 0

intboolstring
intboolstring

Reputation: 7100

Yes.

If you want to visualize that, you can just print the object to see that hash:

public class ClassA {

    private Main main;
    Object obj = new Object;

    public void setMain(Main main) {
        this.main = main;
    }
    methodA() {  //called first
        System.out.println(obj); //you should see the same hash as in methodB
        obj.someFunction();
        main.someFunction();
    }
    methodB() {  //called second
        System.out.println(obj); //you should see the same hash as in methodA
        obj.someOtherFunction();
    }
}

Upvotes: 3

SLaks
SLaks

Reputation: 887355

Yes.

Java will not change objects behind your back.

Upvotes: 2

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