Association , Aggregation and Composition in Java

Zoom Meeting : 21-4-2020

1) Association is a general binary relationship that describes an activity between two classes.

Association can be represented by a line between these classes with an arrow indicating the navigation direction. In case an arrow is on both sides, the association is known as a bidirectional association.

2) Aggregation implies a relationship where the child can exist independently of the parent. Example: Class (parent) and Student (child). Delete the Class and the Students still exist.

3) Composition implies a relationship where the child cannot exist independent of the parent. Example: House (parent) and Room (child). Rooms don't exist separate to a House.

4) A multiplicity could be a number or an interval that specifies how many of the class’s objects are involved in the relationship.