Top 5 Books to Learn Groovy and Grails for Java Programmers - Best of Lot

If you want to learn Groovy and Grails and looking for the best resources then you have come to the right place. Earlier, I have shared some of the must-read Groovy books, and today, I'll share some of the best books to learn Grails for Java developers. Grails is a web application development framework completely written in Groovy. The Grails and Gradle framework are built using the Groovy language. Grails is the framework to develop a web application using Groovy. The concepts within Grails, like interceptors, tag libs, and Groovy Server Pages (GSP) are very similar to what we have in Java.

You'll be amazed at how quickly you can have a first-class web application up and running from ground zero. Grails includes everything you need in a single zip file on a web server (Jetty), a database (HSQLDB), Spring, Hibernate, even a Groovy version of Ant called GANT.

Grails framework is also based upon open source technologies such as Spring, Hibernate, and SiteMesh, which gives it even more powerful and ideal for Java developers.

The Spring Framework provides robust inversion of control and MVC, Hibernate brings a stable, mature object-relational mapping technology with the ability to integrate with legacy systems, and SiteMesh handles flexible layout control and page decoration.

I am assuming you are familiar with the Groovy programming language. Still, if you are not, I suggest you first go through a beginner book on Groovy itself, like the Making Java Groovy, which is an excellent introduction to Groovy for Java developers. 

If you prefer online courses, you can also join The Complete Apache Groovy Developer course, one of the best resources to get up-to-speed with Groovy.  By going through this book or course, you will quickly get up-to-speed in Groovy to start with Grails.

Top 5 Grails Books for Java and Groovy Programmers

Without wasting any more time, here is my list of some of the best Grails books for Java and Groovy developers. The list includes both beginner and intermediate level books to learn Groovy from scratch for Java developers. 

1. The Definitive Guide to Grails 2

The Definitive Guide to Grails 2, by Jeff Brown and Graeme Rocher, is one of the most authoritative books written on Grails. The fact that Jeff is a core Grails committer and Graeme is the head of the Grails project proves my point.

If you are looking for a beginner-level book to learn Grails from scratch then this book is for you. You will learn Grails in a hands-on manner by following non-trivial examples. 

The book is, as it says, definitive, though it's based on Grails 2.0 (the current version is Grails 3.3). Highly recommended. If you want you can also take help from the Mastering Grails course on Udemy for active learning.

2. Grails in Action, Second Edition (Manning)

This is another excellent book to learn about the Grails framework. Authors Glen and Peter have covered most of the core features of the Grails framework. This is a comprehensive book to learn Gradle 2 and full of useful examples and projects. 

In this book, you will learn how to use Grails 2.3 by applying modern Test Driven Development techniques and building a Twitter clone. I always like project-based books and courses as it not only teaches you the theory but also how to use that knowledge in the real world. 

Along the way, you will also learn key skills like how to use Grails with NoSQL database, how to develop RESTFul APIs and web services using Grails, and how to integrate your app with enterprise messaging solutions. 

It talks about plugins, mapping to legacy databases, and even single-page apps, among other things. Overall a fantastic book to learn Grails in depth. Though, for interactive learning, I also suggest you combine this book with the Introduction to Grails course by Dan Bunker on Pluralsight.

3. Grails 2: A Quick-Start Guide, by Ben and Dave Klein 

This is one of the best beginner books on Grails, and you will simply love it. It's a bright, well-written tutorial that will teach you how to build a simple but non-trivial website from start to finish. It may leave you wanting more (that's what the other books are for), but it's an excellent way to get started if you don't have any background in the Groovy or Grails.

I always solve books from Pragmatic Programmer as their books are to-the-point and cover real practical ways of using technology and this book is not an exception. Another good thing is that Pragmatic Programmer is now shared their book on Medium, which means if you have Medium membership then you can read all of their books for free. 

4. Beginning Groovy and Grails: From Novice to Professional

This should be everybody's second Grails book. It's written for developers with some Grails experience and shows what's actually going on under the hood. If you want to use Hibernate from Grails framework then this is the best book to read. You will learn about how to use Hibernate, one of the leading Java frameworks for persistence and ORM. 

The discussion of Hibernate in Grails alone is worth the cost of the book and is better than most of the available Hibernate documentation. Even experienced Java developers who want to use Grails for web application development can read this book to create backend servers in Groovy. 

5. Programming Grails: Best Practices for Experienced Grails Developers 

As the title suggests it best suited for developers, who are using the Grails framework in their day-to-day life and have good exposure to it. If you want to learn Grails in-depth, then you can read this book after reading one of the first three books on this list.

That's all about some of the best books to learn Grails framework. As I said before, you must know Groovy before you start with Grails to get the most benefit from it. Even though most of the Grails book includes the basic introduction of the Grails and Gradle framework, I recommend reading a good book or joining a course on Groovy first to understand its syntax and how it works. My favorite is The Complete Apache Groovy Developer course, but if you prefer books, you can check out my earlier list of good Groovy Books for Java developers.

Further Learning
If you are a curious developer and want to learn and upgrade your skills, here are a couple of great books to explore:

1. 10 Books for Coders of All Levels
2. 5 Books to Learn Java 8 and Functional Programming
3. 5 Books to Learn Spring Framework and Spring Boot
4. 5 Hibernate and JPA Books for Java Developers
5. 20 Books Java Developers Should Read 
6. 5 Books to Learn Advanced Multithreading and Concurrency in Java
7. 5 Book to learn Java Performance Tuning
8. 5 Books to Learn Unit testing in Java with JUnit and Mockito
9. 5 OOP Design Pattern Books for Java Developers
10. 5 Soft Skill Books Programmers Should Read
11. 5 Spring Framework Books Java Developer Should Read
12. 5 Data Structure and Algorithm Books for Programmers
13. 10 Books Every Java Developer Should Read

Thanks for reading this article so far. If you like my recommendation and found these books helpful in learning Grails, then please share them with your friends and colleagues. If you have any questions or feedback or any other great Grails book to include in this list, then please share it with us.