Difference between Association and Aggregation

Prerequisite – Association, Composition and Aggregation in Java

Association: An association is defined as an organization of people with a common purpose and having a formal structure. It represents a binary relationship between two objects that describes an activity. It is a relationship between objects. For example, A doctor can be associated with multiple patients. 

Aggregation: An aggregation is a collection, or the gathering of things together. This relationship is represented by a “has a” relationship. In other words, aggregation is a group, body, or mass composed of many distinct parts or individuals For example, phone number list is an example of aggregation. 

Difference between Aggregation and Association:

Aggregation	Association
Aggregation describes a special type of an association which specifies a whole and part relationship.	Association is a relationship between two classes where one class use another.
It in flexible in nature	It is inflexible in nature
Special kind of association where there is whole-part relation between two objects	It means there is almost always a link between objects
It is represented by a “has a”+ “whole-part” relationship	It is represented by a “has a” relationship
Diamond shape structure is used next to the assembly class.	Line segment is used between the components or the class