Please note that there are different interpretations of the “association” definitions. My views below are heavily based on what you would read in Oracle Certification books and study guides.

Temporary association

A usage inside a method, its signature or as a return value. It’s not really a reference to a specific object.

Example: I park my Car in a Garage.

Composition association

A so-called “STRONG relationship“: The instantiation of the linked object is often hard
coded inside the constructor of the object. It cannot be set from
outside the object. (Composition cannot be a many-to-many
relationship.)

Example: A House is composed of Stones.

Direct association

This is a “WEAK relationships“. The objects can live independent and there are usually setters or other ways to inject the dependent objects.

Example: A Car can have Passengers.

Aggregation association

Very similar to a Direct association. It’s also a “WEAK relationship” with independent objects. However here the associated objects are a crucial part of the containing object.

Example: A Car should have Tires.

Note: Both Direct associations and Aggregation associations are often generalized as “Associations”. The difference is rather subtle.