Association, Aggregation and Composition — a practical guide to association aggregation composition with clear examples you can reuse in real projects.
OOP Tutorial Series (39/65). Prefer one article? Read the complete OOP tutorial.
Short description
Association links objects. Aggregation is a weak “has-a”. Composition is a strong “owns-a” lifecycle relationship.
Relationship summary
Association → uses
Aggregation → has (parts can live independently)
Composition → owns (parts die with the whole)