Object composition in Java

This is a layered model of system construction (design) where a single component references others only through their (public/export) interfaces . The horizontal structure relates different components of same realm that can play the same role in the same layer.

For example, if a class Bulb inherits another class Device, then we can say that Bulb is having is-a relationship with Device , which implies Bulb is a device.

The composition is a design technique in java to implement a has-a relationship . Java Inheritance is used for code reuse purposes and the same we can do by using composition. The composition is achieved by using an instance variable that refers to other objects.29 Eyl 2021

The composition is a design technique in java to implement a has-a relationship . Java Inheritance is used for code reuse purposes and the same we can do by using composition. The composition is achieved by using an instance variable that refers to other objects.29 Eyl 2021

Composition offers better test-ability of a class than Inheritance . If one class consists of another class, you can easily construct a Mock Object representing a composed class for the sake of testing. This privilege is not given by inheritance.

Composition offers better test-ability of a class than Inheritance . If one class consists of another class, you can easily construct a Mock Object representing a composed class for the sake of testing. This privilege is not given by inheritance.

The main reason to use composition is that it allows you to reuse code without modeling an is-a association as you do by using inheritance . That allows stronger encapsulation and makes your code easier to maintain as Joshua Bloch explains in the 3rd edition of his book Effective Java.16 Oca 2018