upcasting with reflection is not allowed

I have structure like this:

public interface InterfaceOne extends InterfaceTwo {}

public interface InterfaceTwo {}

public class ClassOne<T extends InterfaceOne> extends ClassTwo<T> {}

public class ClassTwo<InterfaceTwo> {}

public final class ClassThree extends ClassFour {

    @Override
    public final ClassOne<InterfaceOne> getObjectClassTwo() {
        /*
         * Multiple markers at this line
         * - The return type is incompatible with com.example.ClassFour.getObjectClassTwo()
         * - implements  com.example.ClassFour.getObjectClassTwo
         */
        return new ClassOne<InterfaceOne>();
    }

}

public abstract class ClassFour {

    public abstract ClassTwo<InterfaceTwo> getObjectClassTwo();

}

since ClassOne extends ClassTwo AND InterfaceOne extends InterfaceTwo why can I not say ClassOne<InterfaceOne> overrides ClassTwo<InterfaceTwo>? It would make perfect sense to me, but it is not allowed?

Also when I get rid of <> declaration i get yellow warning and everything works just fine. I would appreciate anyone explaining this to me. Thanks in advance:-)