Continuous Integration with Java

This page explains yml configuration that is specific to Java projects. For a complete yml reference, please read the YML structure page

Our yml configuration is highly customizable. Please read the following sections carefully to learn how to configure your builds.

Basic configuration

The following shippable.yml should get you started with a simple Java project.

language: java

  - oraclejdk8

The snippet above will run the default command described in the default commands section with oraclejdk8. To customize this configuration, please read the sections below.

Setting language and runtime

For Java projects, the language tag should always be set to java. You can set the runtime to any version(s) using the jdk tag:

language: java

  - oraclejdk8

Our official build images, which are used to run your builds by default, come installed with multiple versions of Java.

To find out which versions are supported out of the box for your build image, read our languages overview for Java.

If you want to test against several versions of Java, you can specify multiple runtimes. The snippet below will trigger 2 builds, one against each version:

  - openjdk7
  - oraclejdk7

Important note: The runtime tag only works with official CI images provided by Shippable. If you are using a custom image for your build, you will need to switch the runtime in the ci section of your yml using update-alternatives.

Preparing your environment

If you're running a simple Java build, feel free to skip this section since you should not have to do anything to prepare the environment. Read this section only if your build needs specific environment variables or you have very custom requirements for your build image.

Overriding the default build image

Depending on the language tag in your yml, an official build image is chosen for your build by default, and your build container is started with standard options. To find out the default image used for your builds, please read the Machine images overview.

If the default image does not satisfy your requirements, you can do one of three things:

  • Continue using default image and include commands to install any missing dependencies or packages in your yml
  • Switch your Machine Image to a more recent version that contains what you need
  • Use a custom build image that contains exactly what you need for your CI. Please note that this will add time to your build since the image will be pulled from a registry.

Setting environment variables

You can define any custom environment variables in the env section of your yml. Please read the docs on Environment variables for more information.

Gradle and Ant compatibility

Starting with v7.1.4, the Java drydock images use sdkman to support multiple versions of Gradle and Ant. By default, these images use Gradle 5 and Ant 1.10, which are incompatible with JDK 7. If you need to use Gradle or Ant on the latest images with JDK 7, you must switch to a compatible version of Gradle or Ant in your build using sdkman as shown below:

Using openjdk7 with ant-

language: java

jdk: openjdk7

    - sdk use ant 1.9.9

Using openjdk7 with gradle -

language: java

jdk: openjdk7

    - sdk use gradle 4.10.3

Please review machine images to know exactly what versions of Gradle and Ant are available in the image you are using.

Configuring build and test commands

The ci section should contain all build and test commands you need for your ci workflow. Commands in this section are executed sequentially. If any command fails, we exit this section with a non zero exit code.

Test and code coverage

You can view your test and code coverage results in a consumable format and drill down further to find out which tests failed or which sections of your code were not covered by your tests.

Your tests results data should be in junit format and your code coverage results should be in cobertura or Jacoco format in order to see these visualizations. Test and code coverage results need to be saved to shippable/testresults and shippable/codecoverage folders so that we can parse the reports.

Sample yml snippet using nose and python coverage:

    #Create folders for test and code coverage
    - mkdir -p shippable/testresults
    - mkdir -p shippable/codecoverage

    #Run test and code coverage and output results to the right folder
    - mvn clean cobertura:cobertura

For Jacoco, we also support more advanced reporting formats.

Advanced config

Multi-module Maven builds

When using multi-module (Reactor) builds, please remember to output all the coverage and tests reports to the (top-level) repository directory. This can be tricky, as the Cobertura plugin resolves output directory differently from Surefire plugin. The most straightforward way of dealing with this issue is to define plugin configuration in the top-level module, using shippable/codecoverage path for Cobertura plugin and ../shippable/testresults for Surefire plugin:


Retrying installation of dependencies

Your dependencies can sometimes fail to install due to network glitches or other external transient factors. You can harden the command for installing dependencies by using shippable_retry. We will then retry the command up to 3 times if it returns a non-zero code.

    - shippable_retry mvn install -DskipTests=true

Default commands

If the ci section is blank, we will run some default commands as explained below.

  • If your repository root does not have gradle or maven files, then our Java builder will use Ant. This is the same as the snippet below:
    - ant test
  • If your repository has a pom.xml file at the root, then our Java builder will use Maven 3:
   - mvn install -DskipTests=true
  • If your repository has a build.gradle file at the root, then our Java builder will use gradle:
   - gradle assemble

To avoid executing the default command, include a simple command in like pwd or ls in this section.

Advanced test reports

When using Jacoco for code coverage, you can get standard or advanced reports, depending on what you copy to the shippable/codecoverage folder.

Here is a basic file structure that is needed for seeing both standard and advanced jacoco reports.

 -- site
     -- jacoco
        |    --
        |-- jacoco.xml
  • For standard reports, copy target/site/jacoco/jacoco.xml to shippable/codecoverage

  • For advanced reports, copy target/site/jacoco/ to shippable/codecoverage

For example:

    - mvn install  
    - cp -r target/site/jacoco/ shippable/codecoverage

This will allow Shippable to use additional metadata about your tests to produce more detailed reports.

Check out our Jacoco sample project on Github to see it in action.