Generic type in java for inner classes

Question

I have abstract class with a generic type parameter, but it seems that the inner class can not access this type:

public abstract class DataProcessor<T> {

    protected interface CallBack {
        List<T> parse(String response) throws ServerException, JSONException;// error
    }
}

What's the problem?

---

update:

Usage:

public class XProcessor extend DataProcessor<X>{
}
public class YProcessor extend DataProcessor<Y>{
}

XProcessor xp=new XProcessor();
YProcessor yp=new YProcessor();

xp.setCallback(new DataProcessor.CallBack<X>(){
    ....
});

But I thought that since the XProcessor have defined the X in the class defined, so I wonder if I can ignore the generic parameter like this:

xp.setCallback(new XProcessor.CallBack(){ //without specify the generic type 
    .....
});

Answer 1

It is not possible for you are intending. To avoid compilation error add the type parameter to Callback interface.

public abstract class DataProcessor<T> {

    protected interface CallBack<T> {
        List<T> parse(String response) throws ServerException, JSONException;
    }
}