Question

I want to create an abstract class in java that forces all its subclasses to implement a SwingWorker (plus the SwingWorker‘s abstract doInBackground() and done()).

In AbstractClass –

abstract class Task extends SwingWorker<Void, Void>{};

I would expect this to cause the compiler to throw an exception when an extended class doesn’t implement it, but it doesn’t.

I am also not quite sure how I would go about indicating that I’m overriding this abstract class. Do I redeclare it in the ConcreteClass as follows?

class Task extends SwingWorker<Void, Void>{
  ...
}

or some other way?

Thanks for all your help!

Answer 1

you need to declare the methods also as abstract, like this:

abstract class Task extends SwingWorker {
    @Override
    protected abstract Void doInBackground();
    @Override
    protected abstract void done();
};