Day-to-day development tasks

This page describes how to perform day-to-day development tasks on the PickCells source code.


Using Maven

Getting started

See Maven in 5 Minutes.

Common Maven commands

A summary of common Maven commands can be found at Introduction to the Build Lifecycle. A few of the most useful ones are below.

Validate project

To validate that a project is correct and all necessary information is available, run:

mvn validate

Compile source code

To compile source code, run:

mvn compile

Compiled code is put into target/classes/.

Compile and run tests

To compile and run tests, run:

mvn test

Compiled tests are put into target/test-classes/ and test reports into target/surefire-reports.

Package project

To package a project e.g. into a jar or zip file, run:

mvn package

The package is put into target/, e.g. target/foundationj-datamodel-0.7.0.jar or target/

Verify project

To check the results of integration tests, run:

mvn verify

Install into local repository

To install a package into the local Maven repository, run:

mvn install

By default, the local Maven repository is located in:

Deploy package to remote repository

For authorised users only, to deploy a package to a remote repository, run:

mvn deploy

Remove build artifacts

To remove the target/ directory, run:

mvn clean

View Maven dependencies

To view a Maven dependency tree, using the Apache Maven Dependency Plugin:

  1. Run:

    mvn dependency:tree
  2. You should see something like:

    [INFO] ------------------------------------------------------------------------
    [INFO] Building foundationj-datamodel 0.7.0
    [INFO] ------------------------------------------------------------------------
    [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ foundationj-datamodel ---
    [INFO] org.pickcellslab.foundationj:foundationj-datamodel:jar:0.7.0
    [INFO] +- org.apache.commons:commons-math3:jar:3.4.1:compile
    [INFO] +- com.fathzer:javaluator:jar:3.0.0:compile
    [INFO] +- org.slf4j:slf4j-log4j12:jar:1.7.7:compile
    [INFO] |  +- org.slf4j:slf4j-api:jar:1.7.7:compile
    [INFO] |  \- log4j:log4j:jar:1.2.17:compile
    [INFO] +- junit:junit:jar:4.11:test
    [INFO] |  \- org.hamcrest:hamcrest-core:jar:1.3:test
    [INFO] \- com.carrotsearch:junit-benchmarks:jar:0.2.1:test

To create a plain-text GraphViz dot directed graph file,, with the dependency tree, run:

mvn dependency:tree -DoutputType=dot

To convert a dot file to an image file, using GraphViz’s dot command, run, for example:

$ dot -Tpng -o dependencies.png

Create a test report

To create an HTML test report, using the Maven Surefire Report Plugin, run:

mvn surefire-report:report

Reports are created in target/surefire-reports/ and an HTML version in target/site/surefire-report.html.

Create JavaDoc

To create JavaDoc, using the Apache Maven JavaDoc Plugin, run:

mvn javadoc:javadoc

JavaDoc is created in target/site/apidocs. The entry page for a web browser is index.html.

Check coding style using Checkstyle

Checkstyle is a style checker. It checks Java source code against a coding standard and can highlight issues relating to readability of the source code, its comments and JavaDoc, and certain design issues. See the Checkstyle web site for a list of default checks.

To run Checkstyle, using the Apache Maven Checkstyle Plugin, run:

mvn checkstyle:checkstyle

Checkstyle reports are created in target/ and an HTML version in target/site/checkstyle.html.

To pull together reports from multiple sub-projects, in their parent project, run:

mvn checkstyle:checkstyle-aggregate

Check code coverage using Jacoco

Jacoco is a code coverage library that identifies code that is executed as a side-effect of running tests. To create a code coverage report using its Maven Plug-in, run:

mvn org.jacoco:jacoco-maven-plugin:prepare-agent test org.jacoco:jacoco-maven-plugin:report

Code coverage reports are created in target/site/jacoco:

foundationj-dbm	org.pickcellslab.foundationj.dbm.queries.adapters	Updatable	42	0	2	0	8	0	4	0	3	0
foundationj-dbm	org.pickcellslab.foundationj.dbm.meta	MetaTargetedDataSet	399	0	30	0	76	0	30	0	15	0
foundationj-dbm	org.pickcellslab.foundationj.dbm.meta	Hideable	19	0	0	0	3	0	2	0	2	0
foundationj-dbm	org.pickcellslab.foundationj.dbm.meta Object() {...}	8	0	2	0	1	0	2	0	1	0

Check test coverage using Cobertura

Cobertura is another code coverage library. To create a code coverage report using its Maven Plug-in, run:

mvn cobertura:cobertura

HTML code coverage reports are created in target/site/cobertura. The entry page for a web browser is index.html.

Using continuous integration

Run test coverage using Cobertura

Cobertura results can be obtained by using GitLab Continuous Integration (GitLab CI).

To enable test coverage, edit .gitlab-ci.yml and add:

  stage: test
    - mvn cobertura:cobertura
      - target/site/cobertura

        - public
      - master
      - test-ok
      - "mkdir public"
      - "cp -r  target/site/cobertura/* public"
    stage: deploy

The result can be seen viewed in a web browser.

Browse PickCells JavaDoc

See PickCells JavaDoc.

Using Git and Framagit

About the forking workflow

For an introduction to the “forking workflow” please see Managing multiple developers and version control in our page on Collaborative Development.

Get PickCells repositories

See Get PickCells repositories in Set up a PickCells development environment.

Use branches to develop features, enhancements or bug fixes

It is good practice to use branches to develop features, enhancements or bug fixes. An example of doing this is as follows.

  1. In the clone of the repository on your local machine, create a new branch. See the Git Style Guide for naming conventions for branches.

    git checkout -b some-new-feature
  2. Implement the changes, committing the changes regularly e.g.

    git commit -a -m "Updated ..."
  3. Regularly push the changes in the branch to your remote fork on Framagit e.g.

    git push origin some-new-feature

    You can check the changes have been pushed by looking at your remote fork on Framagit at the URL<YOUR-USER-NAME>/<REPOSITORY-NAME> e.g.

Use merge requests to request PickCells maintainers review and merge your branch

If you want your branch reviewed by the PickCells maintainers and added to the PickCells repositotries:

  1. Visit your remote fork on Framagit at the URL<YOUR-USER-NAME>/<REPOSITORY-NAME> e.g.
  2. Click “Create merge request” to create a “merge request” (also known as a “pull request”).
  3. In Title: enter a meaningful title.
  4. In Description: add additional information.
  5. In Source branch: select the branch in your repository you want to merge e.g. some-new-feature.
  6. In Target branchL: select the branch in the PickCells repository you want your branch to be merged into.
  7. Click “Submit merge request”.

Using Maven and the Git JGit-Flow Plugin

Git-flow is a wrapper around existing Git commands which can help to manage branching within Git. The Maven plugin ‘JGit-Flow’ supports Git-flow style versioning within Maven.


Add the following configuration to a pom.xml file:

                <!-- see goals wiki page for configuration options -->

Additional plugin-specific configuration options are available.

Manage a release

Starting a release creates a release branch and updates POMs(s) with the release versions. To start a release, run:

mvn jgitflow:release-start

When a release branch is started the plugin prompts for the release version. e.g. if the development branch version is 5.1-SNAPSHOT it will assume that the release is 5.1 (though users can override this). This creates a release branch (e.g. release/rev-5.1) and pushes it to the origin` remote.

Finishing a release runs a Maven build (deploy or install), merges the release branch, and updates POMs(s) with development versions. To finish a release, run:

mvn jgitflow:release-finish

This builds, tags and merges the release branch back into the master and development branches. The plugin does the following:

  1. Builds and runs any tests.
  2. Creates a tag with the version number and a specified prefix: e.g. ags/rev-5.1.
  3. Updates the master branch version, e.g. to 5.1, for all parent projects and all it’s sub-modules.
  4. Updates the development branch version to the next snapshot e.g. 5.2-SNAPSHOT (though users can override this).

Manage a hotfix

Hotfix branches like release branches, except they are based on the master branch instead of the development branch.

Starting a hotfix creates a hotfix branch and updates POM(s) with hotfix versions. To start a hotfix, run:

mvn jgitflow:hotfix-start

This behaves in a similar way to mvn jgitflow:release-start but branches off of master.

Finishing a hotfix runs a Maven build (deploy or install), merges the hotfix branch, and updates POM(s) with previous versions. To finish a hotfix, run:

mvn jgitflow:hotfix-finish

This behaves in a similar way to mvn jgitflow:release-finish.

Work on a feature branch

starting a feature creates a feature branch. To start a feature branch, run:

mvn jgitflow:feature-start

This creates a new feature branch. It will prompt for the branch name which will take the format feature/<BRANCH-NAME>. The branch will be pushed to the origin remote automatically.

Finishing a feature merges the feature branch. To finish a feature, run:

mvn jgitflow:feature-finish

This merges a feature branch back into the development branch and pushes the updates to the origin remote.


Create a new Maven project

  1. Create a new Maven project called my-app4.

    mvn archetype:generate -DartifactId=my-app4 -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
  2. Edit the newly-created POM file in my-app4/pom.xml:

    <project xmlns="" xmlns:xsi="" xsi:schemaLocation="">
                  <password>PASSWORD</password>                                                                                                                                            <squash>false</squash>
                 <scmCommentPrefix>[RELEASE] </scmCommentPrefix>
  3. Build the project:

    mvn package
  4. Test the newly compiled and packaged JAR:

    java -cp target/my-app4-1.0-SNAPSHOT.jar

    You should see:

    Hello World!

Add the new project to a repository on Framagit

  1. Log in to Framagit

  2. Click “+” and select “New project”.

  3. Enter Project name: my-app4.

  4. Click “Create project”.

  5. Add your local my-app4 project to Git and push to Framagit:

    git init
    git remote add origin<YOUR-USER-NAME>/my-app4.git
    git add .
    git commit -m "Initial commit"
    git push -u origin master

Use a feature branch

  1. Start a branch called feature-01:

    mvn jgitflow:feature-start

    Invoking jgitflow:feature-start

  2. Check you are on branch feature-01:

    git branch 
  3. Create a new in a text editor.

  4. Add and commit

    git add
    git commit -a -m "Added"
  5. Finish the feature-01 branch:

    mvn jgitflow:feature-finish

    You will see lots of output, ending with

    Invoking jgitflow:feature-finish

  6. Check you are back on the branch development:

    git branch

Use a release branch

  1. Start a release branch

    mvn jgitflow:release-start

    Invoking jgitflow:release-start

  2. Using a text editor, add some more content to `README..

  3. Commit changes to

    git commit -m "Updated"
  4. Finish the release branch:

    mvn jgitflow:release-finish

    Invoking jgitflow:release-finish

  5. The top of the graph showing the branches over time should look something like the following:

    JGitFlow branches

Find out more