Generics inconsistently using Type?

Question

Here's my final class.

public class ActivitiesSQL implements Activities {
  ...

  @Override
  public boolean add( Activity e ) {
    throw new UnsupportedOperationException( "Not supported yet." ); //To change body of generated methods, choose Tools | Templates.
  }

  @Override
  public boolean remove( Object o ) {
    throw new UnsupportedOperationException( "Not supported yet." ); //To change body of generated methods, choose Tools | Templates.
  }
}

public interface Activities extends Repository<Activity, ActivityId> {
    ...
}

public interface Repository<T, ID> extends Set<T> {

  public abstract T findById( ID id );
}

What I'm trying to understand is why the generated code is remove( Object... and add( Activity ...). Why isn't it remove( Activity ... )?

but `add` and `remove` AFAIK are coming from the same place, so shouldn't they both end up with either Object or Activity? in my implementing class — xenoterracide, Feb 03 '14 at 21:23
Where’s the remove method, you’re implementing/overriding, defined? — Jakub Jirutka, Feb 03 '14 at 21:26
I guess it just never occurred to me that would be defined in Set inconsistently I thought it was something I was doing. — xenoterracide, Feb 03 '14 at 21:37

score 3 · Accepted Answer · edited May 23 '17 at 10:31

3

Assuming the Set you are extending is java.util.Set, the argument to remove() is type Object because that's the way it's defined in java.util.Set.

You could define your own remove(T) in Repository and delegate to Set#remove() if you wanted to, but then it wouldn't be an @Override any more.

Generics inconsistently using Type?

1 Answers1