What is composition in oops?

Composition is one of the fundamental concepts in object-oriented programming. It describes a class that references one or more objects of other classes in instance variables . This allows you to model a has-a association between objects.

Association refers to “has a” relationship between two classes which use each other. Aggregation refers to “has a”+ relationship between two classes where one contains the collection of other class objects.

1. Association between two objects that defines the “has-a” relationship is referred to as Aggregation . A specific type of Aggregation that implies ownership is referred to as Composition.

A composition in Java between two objects associated with each other exists when there is a strong relationship between one class and another . Other classes cannot exist without the owner or parent class. For example, A ‘Human’ class is a composition of Heart and lungs. When the human object dies, nobody parts exist.