What is the difference between Composition and Association relationship?

Question

In OOP, what is the difference between composition (denoted by filled diamond in UML) and association (denoted by empty diamond in UML) relationship between classes. I\'m a

Answer 1

Here go a few examples:

• I am an employee of a company, hence I am associated to that company. I am not part of it, nor do I compose it, but am related to it, however.

• I am composed of organs, which unless are transplanted, will die with me. This is composition, which is a very strong bind between objects. Basically objects are composed by other objects. The verb says everything.

• There is also another less bound kind of composition, called aggregation. An aggregation is when objects are composed by other objects, but their life cycles are not necessarily tied. Using an extreme example, a Lego toy is an aggregation of parts. Even though the toy can be dismantled, its parts can be recombined to make a different toy.