I want to ask that a class have several properties one of them is that its object can be created and also it have a constructor at least one. But in case of abstract classes both rules are violated still they are known as abstract classes while interfaces also cannot instantiate object and donot have constructor but they are known as interfaces not interfaces class? and also i want to ask that I've read that we will use abstract classes when we need to update only base class so My question is what is the advantage or purpose of this updation?? I'm not asking about difference between interface and abstract classes.
Thanks in advance!