In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.

There is a reason why Java method modifiers exist. If you call public methods internally and don't understand why, your developers could face major class issues.

If you want to take advantage of sorting methods in Java, you'll need to implement the Comparable interface.

This tutorial explains how a Java HashMap works internally and explores the challenges of implementing it, including buckets, collisions and hash codes.