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, ...

An abstract class is a template definition of methods and variables in a specific class, or category of objects. In programming, objects are units of code, and each object is made into a generic class ...

It's not good enough to simply write code that works. That code must be easily maintained, enhanced and debugged when problems happen. One of the reasons why object-oriented programming is so popular ...