Difference between has-a and composed-of?

In OOP modeling, is there any distinction between a "has-a" relations开发者_Python百科hip and a "composed-of" relationship?

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Both statements usually mean composition.

But it seems to me that composed-of always means composition while has-a sometimes can mean aggregation (but not in the picture below). In UML it looks like:

_{(source: atomicobject.com)}

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Not really, since both indicate that a parent object contains an instance of a child class. It's mostly a semantic difference where "has-a" represents an association between two different objects, where "composed-of" indicates that the child is an integral part of the parent.