Object composition in Java

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.

Composition relationships are part-whole relationships where the part must constitute part of the whole object . For example, a heart is a part of a person’s body. The part in a composition can only be part of one object at a time.

Composition relationships are part-whole relationships where the part must constitute part of the whole object . For example, a heart is a part of a person’s body. The part in a composition can only be part of one object at a time.

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.

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.

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