Objects are descriptions of sets of behaviors, often in the real world, but just as often in an imaginary world.
Classes describe sets of objects which have shared properties.
Object-oriented software engineering has existed in academic and research settings since the late 1960s, undergoing thorough research throughout the 1970s. During the 1980's it became accepted for commercial and industrial use. These are some of the reasons that object-oriented software development is growing in popularity for commercial applications. Managing Object-Oriented Software Develo pment Projects. Due to space constraints the case study is omitted.