what is the difference between abstract classes and interface?

Answer 1

wrong, zen. you can have abstract class without abstract method. and in jdk 1.8 we can have concrete methods in interface.

Answer 2

An abstract class must have at least one methode which is not implemented and which Will bé overide by the sub-class,so here were are in inheritance.But in an interface all méthod aren't implemented,so the role of the interface is to specify a public API,and all of the class which Will implement the interface must overide all methodes

Answer 3

An abstract class has at least one abstract method.
An interface has only abstract methods.

Answer 4

Nick , you're quite right about having an abstract class without defining abstract methods. My question is why would you declare a class as abstract in the first place without having to create a minimum of one abstract method? . Remember the main reason why we make classes as abstract is to allow any component that inherits it provide functionality to that specific abstract method.

Answer 5

we need to declare abstract keyword for class but dont need to do for an interface

Answer 6

In interface all the methods are abstract method whereas in the abstract class may or may not have the abstract method

Answer 7

interfaces do not have an implementation, but rather provide you with a contract you must adhere to.