Moving from Maven to Gradle in Java

In the last few years Apache Maven has become the de-facto build tool for Java and Java EE projects. But for the last two years, Gradle is gaining more and more users. In this post you are going to see how to use Gradle for Java EE projects.

Gradle is a build automation tool like Ant or Maven but introducing a Groovy-based DSL language instead of XML. So as you might expect the build file is a Groovy file.

There are different ways to install Gradle, but for me the best way is using sdkman tool. To install sdkman tool simply run: $ curl -s get.sdkman.io | bash

After that you can init sdkman by running: $ source "$HOME/.sdkman/bin/sdkman-init.sh"

With sdkman installed, installing Gradle is as easier as running: $ sdk install gradle

Now you can start creating the build script. The first thing to do is creating a settings.gradle where in this case we are going to set the name of the project.

rootProject.name = 'my-javaee'

This file is also used in case of multiple module projects.

Last file you might need is one called build.gradle which manages all the build process.

apply plugin: 'war'

group = 'org.superbiz'
version = '1.0-SNAPSHOT'
description = "My JavaEE project"

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
mavenCentral()        
}

dependencies {
    providedCompile group: 'javax', name: 'javaee-api', version:'7.0'
}

Notice that the first line indicates that what you are going to build is a war project.  Then project properties are set like the group, version, description or Java compilation options. Finally only one dependency is required and with provided scope since the implementation is provided by the application server.

Note that providedCompile scope is only available if you are using the war plugin. If you are using another plugin like java, then you will need to implement this function by yourself (at least at the time of writing this post with Gradle  2.7).

And that's all, pretty compact, only 16 lines and no verbose information. Of course, now you will need to add more dependencies like JUnit or Arquillian with testCompile scope or any other extra library required in your code like the well known apache-commons dependency; but this is a story for another post.