What is composition in OOP in Java?

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. You can find such relationships quite regularly in the real world.

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How do you find aggregation in Java?

Aggregation in Java is a relationship between two classes that is best described as a “has-a” and “whole/part” relationship . It is a more specialized version of the association relationship. The aggregate class contains a reference to another class and is said to have ownership of that class.

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How do you show aggregation in UML?

Aggregation relationship is represented by a straight line with an empty diamond at one end . The composition relationship is represented by a straight line with a black diamond at one end. In UML, it can exist between two or more classes. It is a part of the association relationship.

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