How do you extend a generic abstract class

[Seema Kekre]

Code reference Generics Question

 
abstract class ABS<K extends Number>  
 {  
     public abstract <K> ABS<? super Number> useMe(ABS<? extends K> k); //1
 }
 class SubABS extends ABS{ //2
	@Override
	public ABS useMe(ABS k) { //3
		return new SubABS();
	}
 }

At Line 2, I tried
class SubABS<K> extends ABS<K>,
class SubABS<K extends Number> extends ABS<K extends Number>
and all variations of this, finally it compiles with class SubABS extends ABS, and the warning that raw types are used.

When I use Eclipse to implement the unimplemented methods, I get the method on 3. When I used the exact signature in 1, I get an error
Multiple markers at this line
- Name clash: The method useMe(ABS<? extends K>) of type SubABS has the same erasure as useMe(ABS) of type
ABS but does not override it
- The method useMe(ABS<? extends K>) of type SubABS must override a superclass method

How can I extend this abstract method correctly using Generics and why am I getting the above issues?

[Christophe Verré]

class ABS2<K extends Number> extends ABS<K>

[Seema Kekre]

Now it all compiles fine.
I infer that ABS<K> is required because we have already defined what K is in the abstract class, then why do I need to redefine K for ABS2?

[Leon Omk]

Seema Kekre wrote: Now it all compiles fine.
I infer that ABS<K> is required because we have already defined what K is in the abstract class, then why do I need to redefine K for ABS2?

I have the same question.

[Christophe Verré]

You need to tell which class you are actually using for ABS. If you are not using any generic type in ABS2, you can also define the class like :

class ABS2 extends ABS<Number>

or refine it to Double for example:

class ABS2 extends ABS<Double>

[Seema Kekre]

So either you use ABS to define the type of the subclass if you dont want the subclass to use Generics, or use Generics wrt K's definition of the superclass. Right?