Access object created in innerClass from elsewhere java

Question

so i have outerClass and innerClass, and i want to access the object created from innerClass using outerClass, example:

public Class outerClass{
    Class innerClass{
        //properties
    }
}

so what i want to do is something like this:

public class Main {
    public static void main(String [] args) {
        outerClass outerObj = new outerClass();
        outerClass.innerClass innerObj = outerObj.new innerClass();

        //this is what i want:
        outerObj.innerObj;
    }
}

it might be complicated but what i want to do is get the innerObject, using only outerObject

So what is the problem ? – Suresh Atta Mar 11 '16 at 12:43 — Suresh Atta, Mar 11 '16 at 12:43
line below comment doesnt work – nikagar4 Mar 11 '16 at 12:46 — nikagar4, Mar 11 '16 at 12:46
Create innerObj in your outerClass. – krzydyn Mar 11 '16 at 12:46 — krzydyn, Mar 11 '16 at 12:46

score 3 · Answer 1 · edited Mar 11 '16 at 13:11

3

This would work:

public class outerClass{
    public static class innerClass{
        //properties
    }
}

edited Mar 11 '16 at 13:11

Pragnani

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answered Mar 11 '16 at 12:45

Prashant

4,775
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I thnk it is a valid answer – Pragnani Mar 11 '16 at 12:51

score 1 · Accepted Answer · answered Mar 11 '16 at 12:47

1

public Class outerClass{
    Class innerClass{
        //properties
    }

    public innerClass innerObj;
}

outerObj.innerObj = outerClass.new innerClass();

answered Mar 11 '16 at 12:47

Nadir

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yes that's the solution i came up with but is there any easier way? – nikagar4 Mar 11 '16 at 12:48
@nikagar4 What do you mean by easier ? – Suresh Atta Mar 11 '16 at 12:48
To be able to perform `outerObj.innerObj` there is no other way – Nadir Mar 11 '16 at 12:49
is there a way to do that without that extra property called "innerObj"? – nikagar4 Mar 11 '16 at 12:49
@nikagar4 Then you shouldn't say `and i want to access the object created from innerClass using outerClass`. Create a separate class. – Suresh Atta Mar 11 '16 at 12:50
this is the best solution in my opinion so ill stick with this – nikagar4 Mar 11 '16 at 12:54

score 1 · Answer 3 · answered Mar 11 '16 at 12:48

1

outerClass.innerClass innerObj = outerObj.new innerClass();

innerObj is a local variable. You can refer to it directly as

innerObj

answered Mar 11 '16 at 12:48

Andy Turner

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i want to access it from another class – nikagar4 Mar 11 '16 at 12:50
Then you'd need to pass it to the other class. It's just a plain old local variable. `outerObj` doesn't keep a hold of a reference to `innerObj` (but `innerObj` *does* keep hold of a reference to `outerObj`). – Andy Turner Mar 11 '16 at 12:50
yes i understand but i wanted to be able to access it using only outerClass – nikagar4 Mar 11 '16 at 12:53
@nikagar4 then you don't understand. You can't access it using only `outerClass` because `outerClass` (or `outerObj`) doesn't keep a reference to `innerObj`, unless you actually add a reference to the instance to the outer class, like Nadir suggests. – Andy Turner Mar 11 '16 at 12:54

score 1 · Answer 4 · edited Mar 11 '16 at 13:09

For a non-static inner class, the compiler automatically adds a hidden reference to the "owner" object instance. When you try to create it from a static method (say, the main method), there is no owning instance. It is like trying to call an instance method from a static method - the compiler won't allow it, because you don't actually have an instance to call.

So the inner class must either itself be static (in which case no owning instance is required), or you only create the inner class instance from within a non-static context.

So make your innerClass static

public static class innerClass{
        //properties
    }

You can call

outerClass.innerClass innerObj = new outerClass.innerClass();

If you want to access fields only via dot(.) notation should consider using

static inner field in your outerClass like a PrintStream in System class

Example:

public class outerClass{
    public static innerClass innerObject = new innerClass();
    static  class  innerClass{
            //properties
        }
    }

and then in main method

outerClass outerClass= new outerClass();
        outerClass.innerObject.yourfied

Access object created in innerClass from elsewhere java

4 Answers4