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 ...

When compiling class initializers and class initialization blocks, the Java compiler stores the compiled bytecode (in top-down order) in a special method named <clinit>().

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

Since objects generally represent people, places, or things, a basic method of identifying objects is to pick out the nouns used in a sentence. Here’s a simple example.

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 ...

However, the Java Platform provides a data structure that greatly simplifies the use of reference objects like this, called the java.util.WeakHashMap class. WeakHashMap works exactly like a hash ...

A method might accept a specific type and its subclasses, but you want to restrict usage to a select few implementations of your own design. Java's open inheritance model can feel like an open ...