作者彙整: Jeff Friesen

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. This is also true for any classes and other reference types that you create.

The first half of this tutorial on Java inheritance showed you the basics of inheritance, specifically how to use Java’s extends and super keywords to derive a child class from a parent class, invoke parent class constructors and methods, override methods, and more. Now, we’ll turn our focus to the mothership of the Java class inheritance hierarchy, java.lang.Object.

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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 parent class constructors and methods, and override methods. In Part 2 you’ll tour java.lang.Object, which is Java’s superclass from which every other class inherits.

To complete your learning about inheritance, be sure to check out my Java tip explaining when to use composition vs inheritance. You’ll learn why composition is an important complement to inheritance, and how to use it to guard against issues with encapsulation in your Java programs.

To read this article in full, please click here

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 parent class constructors and methods, and override methods. In Part 2 you’ll tour java.lang.Object, which is Java’s superclass from which every other class inherits.

To complete your learning about inheritance, be sure to check out the Java 101 composition and inheritance primer. You’ll learn why composition is an important complement to inheritance, and how to use it to guard against issues with encapsulation in your Java programs.

To read this article in full, please click here