For example, the sweater may be dry-cleaned, the color may be changed, it may be worn. Methods describe activities the objects might perform. For example a car may transport you from place to place. Events are things that initiate an activity that the object is designed to perform. For example, when you put your foot on the car's break, the car slows to a stop.
Message are a type of event received as a communication from another source.
Similar objects may be grouped into a class of more generic items. For example, a blue sweater is a sweater, but also a garment. A dress is also a garment. A jacket is also a garment. A sweater, dress, and jacket have common properties defined for garment.