Classes, fields, methods, constructors, and objects are the building blocks of object-based Java applications. This Java tutorial teaches you how to declare classes, describe attributes via fields ...

This post explains how to use classes in Java to build objects and organize your code. Also learn: constructors, static methods, and more!

Object-oriented systems are usually partitioned into layers of related responsibilities and only dependencies in one direction are allowed, from higher layers (more specific, less reusable) to lower ...

What is the contract between equals() and hashcode()? Learn how these methods work together when comparing objects in Java.

Most Android developers will use Java to write their apps. Java is an object oriented programming language. But what precisely does that mean?

Finally, we learned that everything in Java is an object, except primitive data types. Because so much of this programming style involves objects and classes, we will now look at each of these ...

Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.