Book Image

Learn Java with Projects

By : Dr. Seán Kennedy, Maaike van Putten
5 (3)
Book Image

Learn Java with Projects

5 (3)
By: Dr. Seán Kennedy, Maaike van Putten

Overview of this book

Learn Java with Projects stands out in the world of Java guides; while some books skim the surface and others get lost in too much detail, this one finds a nice middle ground. You’ll begin by exploring the fundamentals of Java, from its primitive data types through to loops and arrays. Next, you’ll move on to object-oriented programming (OOP), where you’ll get to grips with key topics such as classes, objects, encapsulation, inheritance, polymorphism, interfaces, and more. The chapters are designed in a way that focuses on topics that really matter in real-life work situations. No extra fluff here, so that you get more time to spend on the basics and form a solid foundation. As you make progress, you’ll learn advanced topics including generics, collections, lambda expressions, streams and concurrency. This book doesn't just talk about theory—it shows you how things work with little projects, which eventually add up to one big project that brings it all together. By the end of this Java book, you’ll have sound practical knowledge of Java and a helpful guide to walk you through the important parts of Java.
Table of Contents (22 chapters)
1
Part 1: Java Fundamentals
9
Part 2: Object-Oriented Programming
15
Part 3: Advanced Topics

Examining default and static interface methods

Before Java 8, only abstract methods were allowed in interfaces. This meant that if you introduced a new abstract method to an existing interface, the classes that had already implemented that interface would break. This was inconvenient for not only Java developers but also the designers of Java.

This all changed in Java 8, with the introduction of both default and static methods. One of the primary drivers for introducing default methods was to be able to introduce code into the interface and not break the existing client base. This maintained backward compatibility. In addition, this new code is automatically available to clients implementing that interface.

A primary driver for the introduction of static methods was to keep utility code local to the interface rather than having it in a separate class, which was the case before their introduction.

Let’s discuss them in turn, starting with default methods.

‘...