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 ...

The Java tutorial Java 101: Classes and objects in Java introduces the fundamentals of Java classes and objects, including how to declare classes, describe attributes via fields, describe behaviors ...

Classes and objects in Java must be initialized before they are used. You’ve previously learned that class fields are initialized to default values when classes are loaded, and that objects are ...

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 ...