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

Hashing and overriding hashCode()

Hashing is an important concept in Java. It is used to efficiently store and retrieve data in various data structures, such as HashMaps and HashSets. It’s also a very interesting topic. You’ll get quite far without understanding what this does, but at some point, you may wonder about the horrible performance of your HashMap class. And understanding what is going on is not possible without understanding hashing. So, let’s discuss the basic concepts of hashing, the role of the hashCode() method in collections, and best practices for overriding the hashCode() method in your custom classes.

Understanding basic hashing concepts

Hashing is a method that transforms data into a piece of code called a hash code. Think of it like taking a huge pile of books and assigning each book a unique number. A good hash function should give different books different numbers and spread them evenly. This makes it easy to find and organize the books...