The first half of this introduction to Java inheritance teaches you how to use the extends keyword to derive a child class from a parent class, invoke parent class constructors and methods, and ...

Everything is an object in the marvelous world of managed code, from simple entities, such as numbers and strings, to complex UI objects, such as controls and forms. As a matter of fact, a form is ...

When designing applications, it is important to know when to use an abstract class and when to use an interface. Although abstract classes and interfaces seem similar in some ways, there are key ...

Extensible applications allow you to add functionality without rewriting your application: you dynamically select the classes that make up your application at runtime rather than design time. I once ...