How to Set Up a New IntelliJ Project with Gradle

saylerb

Step 1: Install things

Java 1.8, which is the current version of Java in Long Term Support as of this article, has most of the modern features that anyone new to Java will need.
Exercism has a pretty good page for instructions on installation. If you want to download an older version of Java, you’ll have to make some adjustments to the installation instructions. For example, if you want to download Java 8 on a Mac with the Homebrew package manager. You can do:

brew tap caskroom/versions
brew cask install java8

You don’t need to install Gradle, since IntelliJ has a Gradle wrapper out of the box.

When you open up IntelliJ, there should be a dialog that is open.
Select Create a Project.
The Left panel will show different types of projects. Select Gradel. Gradle is a build tool and dependency manager. Build scripts are written in Groovy, a dynamic langauge that feels like a mix of Ruby and Java.
Select your project SDK in the top drop down menu. The version of Java you installed should be there.
On the next screen, you’ll see GroupID, ArtifactID, and Version. These are maven artifacts (Maven is another build tool that uses an XML configuration file) These aren’t that important to us, but we have to fill them out. GroupID - usually identifies the organization/team for a particular project. E.g. com.companyname.project. If it’s a personal project, you can just use your name. ArtifactID - the name to give to your jar without a version number. E.g. MyFirstProject. * Version - the version number. This would increment with each release if you were distributing the software. e.g. 1.0
On the next screen, make sure to check Create separate module per source set, and Use default gradle wrapper. You can use the Project JVM for Gradle JVM (the same one you specified earlier)
On the next screen select the location of the project to save
It will prompt you that the file is going to be created by IntelliJ, click yes.
Intially, your Gradle build will start syncing.

In the root of the project, you should see file called build.gradle that was generated for you. Gradle makes it really easy to build your project (compile your Java source files). It can also do many other things, including running your tests, and creating a JAR file containing your classes. The build.gradle file is written in Groovey, a dynamic language that feels like a mix of Java and Ruby.
If you step into the build.gradle, you’ll see that it already has jUnit specified as a dependency, which is great.

A simple .gitignore for this project could be:

.idea/
build
.gradle
!gradle-wrapper.jar

Ignoring the .idea/ directory is optional. JetBrains would probably recomend publishing it, because it contains metadata about your IDE setup which can be useful for others working on the same team. If you think it’s valuable to publish, by all means go ahead and do it.
Ignore the build directory. This is where gradle will put the compiled Java classes. Since anyone who downloads your source code can build the project themselves, there’s no need to publish this directory.
Ignore the .gradle directory.
Don’t ignore the gradle-wrapper.jar. This can allow anyone to pull the project down and build without having to install Gradle manually.

By default, Gradle expects the following directory structure:

src
├── main
│   └── java
│       └── hello
│           └── Hello.java
└── test
    └── java
        └── hello
            └── HelloTest.java

And that’s pretty much it to get started with a new project.