Multiple levels of abstraction facilitate the presentation and management of varying amounts of detail. Abstraction is a coping strategy that helps us deal with complexity. There was insufficient time in the workshop to discuss composition. Both class and type are classification mechanisms. However, class is a real-world or analysis concept and type is a design or implementation concept.
Classes classify objects, and types describe object representations.
Specifics for class include the following. Since an object is subject to change, class membership is dynamic. Moreover, the membership predicate for a class can change too, which also causes class membership to be dynamic. Additional observations about classes were given as follows. An object is a member of some universe of objects.