Classes, fields, methods, constructors, and objects are the building blocks of object-based Java applications. This Java tutorial teaches you how to declare classes, describe attributes via fields ...

The more familiar you are with Object and its methods, the more you can do with your Java programs.

Object-oriented systems are usually partitioned into layers of related responsibilities and only dependencies in one direction are allowed, from higher layers (more specific, less reusable) to lower ...

Instance variables contain data associated with an object, such as its description, the types of messages it can receive, the objects it can receive messages from, and the objects it can send messages ...