Design patterns book: factory pattern UML and pseudo code confusion

Hi!

I have a question about the factory pattern example ( GUIFactory ):
- I see in the UML diagram of the GUIFactory the Button and Checkbox as abstract classes

but in the pseudocode, I see the implementation as interfaces:

interface Button is
    method paint()
interface Checkbox is
    method paint()

So my question is:

- In UML when we set an "Italic class" it could be an abstract class or interface or is a mistake in the UML diagram?

I also get confused because the Button and Checkbox arrows look like the one of inheritance/generalization ( white arrow with line ) relationship? and not as interface implementation ( arrow with dotted line )

I understand the difference between them, but my confusion is because the center interface of GUIFactory is presented as an interface and implemented in the pseudo-code as an interface

interface GUIFactory is
    method createButton():Button
    method createCheckbox():Checkbox