Trail: Learning the Java Language

The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
SeeDev.java for updated tutorials taking advantage of the latest releases.
SeeJava Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
SeeJDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.

Lesson: Classes and Objects

With the knowledge you now have of the basics of the Java programming language, you can learn to write your own classes. In this lesson, you will find information about defining your own classes, including declaring member variables, methods, and constructors.

You will learn to use your classes to create objects, and how to use the objects you create.

This lesson also covers nesting classes within other classes, and enumerations

Classes

This section shows you the anatomy of a class, and howto declare fields, methods, and constructors.

Objects

This section covers creating and using objects. You will learn how to instantiate an object, and, once instantiated, how to use thedot operator to access the object's instance variables and methods.

More on Classes

This section covers more aspects of classes that depend on using object references and thedot operator that you learned about in the preceding section: returning values from methods, thethis keyword, class vs. instance members, and access control.

Nested Classes

Static nested classes, inner classes, anonymous innerclasses, local classes, and lambda expressions are covered.There is also a discussion on when to use which approach.

Enum Types

This section covers enumerations, specialized classes that allow you to define and use sets of constants.