When you work on a Java project, you want to get an idea of your code quality.

Of course, “good” code doesn’t mean, the code is error-free, but on the other hand, if your code is seen as “bad”, you can be pretty sure, that it will become unmaintainable very soon.

Because of this, tools like SonarQube can be helpful to give an unbiased insight into how well your code might be, according to established coding standards.

First, you have to set up a SonarQube server, which is a very easy task, if you’re on an Ubuntu system:

Add the following line to your /etc/apt/sources.list:

deb http://downloads.sourceforge.net/project/sonar-pkg/deb binary/

and then run the well known and to-be-expected

apt-get update
apt-get install sonar

commands.

Assuming, that you already have got a PostgreSQL database running, create a user “sonar” with password “sonar” and enable the few PostgreSQL-related parts in /opt/sonar/conf/sonar.properties.

Finally, as root, start SonarQube with

/etc/init.d/sonar start

and maybe add it to /etc/rc.local

The next step is now, to prepare your project’s build.gradle script to ensure, that not only the SonarQube is filled with data, but also at least measures your test coverage.

The relevant parts are:

apply plugin: "sonar-runner"
apply plugin: "jacoco"

sonarRunner {
        sonarProperties {
                property "sonar.host.url", "http://localhost:9000"
                property "sonar.jdbc.url", "jdbc:postgresql://localhost:5432/sonar"
                property "sonar.jdbc.driverClassName", "org.postgresql.Driver"
                property "sonar.username", "sonar"
                property "sonar.password", "sonar"
                property "sonar.projectName", "rmmusic"
                property "sonar.jacoco.reportPath", "build/jacoco/test.exec"
                property "sonar.java.source property", "1.8"
        }
}

jacoco {
    reportsDir = file("build/tmp/jacoco.exec")
}

Additionally, log in as admin user into your SonarQube instance and in Settings->System->Update Center, add a few plugins:

• Java
• Checkstyle
• Sonargraph
• PMD
• Timeline
• Findbugs

and restart SonarQube.

As admin user, you should then set now a quality profile, e.g. the FindBugs profile

Now, when you run the gradle target sonarRunner, all those tests will be executed automatically and you’ll get detailed insights into your code and its quality.