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.

There are over 40 functional interfaces listed in the java.util.functions package, which can make the prospect of functional programming in Java a somewhat daunting task.

For an introduction to Java interfaces, including the difference between classes and interfaces, see my Java 101 tutorial Working with interfaces in Java. Nesting interfaces in classes ...

A tutorial highlighting the various design patterns in Java. Learn about the benefits and different types of design patterns.