Abstract Class Extends Interface Java

However with abstract classes you can declare fields that are not static and final and define public protected and private concrete methods.

Abstract class extends interface java. Abstract classes are similar to interfaces. In other way there can be a super interface for an interface but there can not be a superclass for an interface. It can have abstract and non abstract methods method with the body. Method bodies exist only for default methods and static methods.

Another way to achieve abstraction in java is with interfaces. Along with abstract methods an interface may also contain constants default methods static methods and nested types. The class xyz is implementing only interface b. Note that even though class xyz is implementing the interface b the interface a is automatically available to the class as interface b is extending the interface a.

2an interface can not extend inherits any other class abstract class with non abstract methods and pure abstract class abstract class having all abstract methods. Therefore when you create a subclass extended an abstract class you need to implement the abstract method that was in the abstract class if any otherwise the subclass would be still an abstract class which cannot be instantiated. I want to extend the abstract class by another abstract class and then implement the extended abstract class. Before learning the java abstract class lets understand the abstraction in java first.

Is it possible if yes whether its a good approach in point of view regarding oops. 3 an abstract class can have both abstract and concrete methods. A class implements an interface thereby inheriting the abstract methods of the interface. With interfaces all fields are automatically public static and final and all methods that you declare or define as default methods are public.

One class can implement several interfaces whereas it can extend just one class abstract or not. Writing an interface is similar to writing a class. You cannot instantiate them and they may contain a mix of methods declared with or without an implementation. 1 an abstract class can extend only one class or one abstract class at a time an interface can extend any number of interfaces at a time.

1 an interface can extend inherits only another interface. In below java code example the interface b is extending interface a. The class has to implements both the methods from interface a and b ie. Abstract class in java a class which is declared with the abstract keyword is known as an abstract class in java.