Articles by Jeff Friesen

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 initialized via constructors, but there is more to initi…

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 initialized via constructors, but there is more to initi…

Polymorphism refers to the ability of some entities to occur in different forms. It is popularly represented by the butterfly, which morphs from larva to pupa to imago. Polymorphism also exists in programming languages, as a modeling technique that …

Polymorphism refers to the ability of some entities to occur in different forms. It is popularly represented by the butterfly, which morphs from larva to pupa to imago. Polymorphism also exists in programming languages, as a modeling technique that …

In Java 101: Inheritance in Java, Part 1, you learned how to leverage inheritance for code reuse, by establishing is-a relationships between classes. Composition is a closely related programming technique that is used to establish has-a relationships i…

In Java 101: Inheritance in Java, Part 1, you learned how to leverage inheritance for code reuse, by establishing is-a relationships between classes. Composition is a closely related programming technique that is used to establish has-a relationships i…

Java provides a standard class library consisting of thousands of classes and other reference types. Despite the disparity in their capabilities, these types form one massive inheritance hierarchy by directly or indirectly extending the Object class…

Java provides a standard class library consisting of thousands of classes and other reference types. Despite the disparity in their capabilities, these types form one massive inheritance hierarchy by directly or indirectly extending the Object class…

Java supports class reuse through inheritance and composition. This two-part tutorial teaches you how to use inheritance in your Java programs. In Part 1 you’ll learn how to use the extends keyword to derive a child class from a parent class, invoke…

Java supports class reuse through inheritance and composition. This two-part tutorial teaches you how to use inheritance in your Java programs. In Part 1 you’ll learn how to use the extends keyword to derive a child class from a parent class, invoke…