Java generics- constructor type

Question

public class AClass<X extends AnInterface>{

    public AClass(X x){
    }

}

public class Y implements AnInterface{

}

In the calling code if I have:

public static<X extends AnInterface> void main(String args){

    AnInterface y = new Y();
    AClass a = new AClass<AnInterface>(y);

}

I should be able to get this to work using X in the constructor for AClass right? I am getting errors telling me the contructor for AClass should be of type AnInterface??

EDITED to change AClass a = new AClass<AnInterface>(y);

TedTrippin · Accepted Answer · 2012-07-11 09:26:01Z

2

You need to tell AClass what type its expecting.

    public static void main(String args){
        AnInterface y = new Y();
        AClass<AnInterface> a = new AClass<AnInterface>(y);
    }

answered Jul 11, 2012 at 9:26

TedTrippin

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2 Comments

intrigued_66 Over a year ago

Sorry, I do have that- I had to re-type my code out here and missed that bit. Its complaining about the type of the constructor for AClass.

TedTrippin Over a year ago

Look at my code and see if you can spot the difference :) You need to declare a as AClass<AnInterface> too. Thing is, I suspect there is a better solution to your problem although can't tell from this example.

XU3352 · Accepted Answer · 2012-07-11 09:21:30Z

0

public static void main(String[] args) {
    AnInterface y = new Y();
    AClass a = new AClass(y);
}

answered Jul 11, 2012 at 9:21

XU3352

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1 Comment

TedTrippin Over a year ago

That doesnt get rid of the warning.

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