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

Exploring stream laziness

The principle of lazy evaluation is that you get what you need, only when you need it. For example, if shopping websites such as Amazon were to display 10,000 records to a user, the principle of lazy evaluation would be to retrieve the first 50 and while the user is viewing these, retrieve the next 50 in the background. An eager evaluation would be to retrieve all 10,000 records in one go. With regards to streams, this means that nothing happens until the terminal operation gets called.

The pipeline specifies what operations we want performed on the source and in what order. As nothing happens until the terminal operation runs, Java is aware of the full pipeline. This enables Java to introduce efficiencies whenever possible. For example, why run an operation on a piece of data if that operation is not required? This could arise in the following situations:

  • We have already found the data item we are looking for
  • We may have a limit set of the...