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

Understanding the difference between method definition and method execution

For those new to programming, it may surprise you to know that there are two parts to having a method do something. Firstly, we must code the method (the method definition). This is similar to a bank machine on the street – it just sits there, doing nothing, waiting to be used. Secondly, we must execute the method (the method execution). This is similar to a customer “using” the bank machine. Remember that the main method is the only method that is automatically executed by the JVM. Any other method calls have to be explicitly coded.

Now, let’s examine the method definition and method execution in turn.

Method definition

The method definition (declaration) is the method code itself - this is the block of code that is executed when the method is called. Figure 7.4 presents the syntax:

Figure 7.4 – The syntax of the method definition

Figure 7.4 – The syntax of the method definition

In...