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 ...

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

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 ...

Reference objects aren't just useful when memory is at a premium; they can also be used to provide slick caching abilities to any application.