Abstract Classes and Interfaces Part 1 Framework for Component-Based Design • Framework for design reuse, enabled by software interfaces
otherwise it must be an “abstract” class (more later) • An interface can extend other interfaces • A class can extend only one class, but it can implement
Java Classes et méthodes abstraites ▫ Exemple public abstract class AnimalCompagnie{ Soit sous forme d'interface de méthodes abstraites dont on est
class Circle implements Drawable{ 10 public void draw(){System out println("drawing circle");} 11 } 12 //Using interface: by third
public abstract class GeometricObject { private String color = "white"; private boolean filled; private java util Date dateCreated;
chapter: abstract classes, interfaces, instanceof operator, final methods, and final recommended Java solution in this case is an abstract class
Since Java 8, it can have default and static methods also 2) Abstract class doesn't support multiple inheritance Interface supports multiple inheritance
Interfaces • A Java interface is a collection of abstract methods and constants • An abstract method is a method header without a method body
Subclasses must implement all abstract methods, or must also be abstract classes • Why make a method abstract? – Provide some default behaviors in concrete