Contributing to Orekit

Orekit is free software, which means you can use the source code as you wish, without charges, in your applications, and that you can improve it and have your improvements included in the next mainstream release.

If you are interested in participating in the development effort, thank you very much! Here are the steps you will need to follow:

  1. If not already done, create an account on the Orekit forge
  2. Fork the Orekit project using the link on the main page of the forge (red rectangle on the following image). fork
  3. Pull the develop branch of Orekit.
  4. Create a new branch on your fork. The branch must:
    • have develop branch as source branch.
    • have a name related to the future contribution. For instance, if you want to correct an issue, the name must be issue-XXX where XXX represents the issue number.
  5. Be sure to activate checkstyle (use the checkstyle.xml file at the root of the project) to help you follow the coding rules of Orekit (see Eclipse example below).
  6. Perform your developpement and validation.
  7. Update the changes.xml file in src/changes/ directory (see former entries to help you).
  8. Run all Orekit tests to ensure everything work.
  9. Commit your code on your branch.
  10. Submit a merge request on the forge (click on the green item). Be sure to submit it on the develop branch. By default, GitLab will propose you to submit it on the master branch. merge requests
  11. Wait for one of the developers to merge your code on the repository.

If your contribution consists of adding or changing a lot of code lines or class architectures, we invite you to discuss the contribution before on the Orekit forum. Indeed, a developer can be currently working on the code you want to modify. Moreover, the forum is a good place to discuss future additions to Orekit.

If you have any question during your contribution you can also visit the forum and ask them. The larger the community is, the better Orekit will be. The main rule is that everything intended to be included in Orekit core must be distributed under the Apache License Version 2.0.

Configure Orekit checkstyle

Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard. It automates the process of checking Java code to spare humans of this boring (but important) task. This makes it ideal for projects that want to enforce a coding standard.

Configuring checkstyle can be a difficult task when installing Orekit in an Integrated Development Environment (IDE). However, it is an important step for contributing to the library.

Configure checkstyle in Eclipse

Here are the steps you will need to follow to configure checkstyle in Eclipse

 Installing Eclipse Checkstyle plugin.

In your Eclipse IDE, select Help –> Install New Software…

Pressing the Add… button at the top right of the install wizard will display a small popup asking for the name and location of a new software site.

Press Add to close the popup.

Select Checkstyle in the Install window and click on Next >. Proceed to the end of the wizard, accepting the licenses of the plugin and installing it.

 Configuring the project.

To create the local configuration, select Properties by right-clicking in the context menu of the project explorer panel.

In the Properties popup, select Checkstyle entry.

In this second popup (i.e. Local Check Configurations) define a project relative configuration as presented in the figure below. We browse the workspace to select our checkstyle.xml file, and we tick the Protect Checkstyle configuration file check box to prevent the plugin to alter the configuration.


The property must be defined by pressing the Additional properties… button, which will trigger yet another popup into which the property can be configured as shown below.


Pressing the OK button in the last open popup ends the local check configuration creation. Select the Main tab in the first popup, which should still be opened.

In the Main tab, un-tick the Use simple configuration checkbox at the top right. A few buttons should appear, allowing to remove the default Sun checks global configuration (selecting it and pressing the Remove button) and add our local configuration instead (pressing the Add… button). Using for example src/main/java/.*.java will apply checkstyle only to the files in the src/main/java directory and not to the files in the src/test/java directory.


Press OK and Apply and Close to finish the installation.

 Activate the checkstyle.

Select Checkstyle –> Activate Checkstyle by right-clicking in the context menu of the project explorer panel.