Question

This is my scenario in Java:

interface I{}
class A implements I{}
class B extends A{}

So, now which class needs to implement the interface’s I methods? What if A and B classes share implementation?
Best regards

Answer 1

class A has to provide all implementations since it’s not abstract. See here for more details.

class B can override any/all of those methods.

If you make A abstract (as a class), then it can provide abstract methods for those methods in the interface (essentially just declaring them as abstract) and B would provide the only implementation.