The Codename One SDK is published as a Maven multi-module project. Building the aggregator in the /maven directory compiles every module, installs the artifacts into your local Maven repository, and lets you depend on the exact snapshot you cloned from GitHub.

Prerequisites

Codename One uses multiple JDKs and Maven profiles during the build. Make sure your development machine includes the following tooling (see BUILDING.md for platform-specific installation tips):

  • JDK 8 (required for the core build of the framework itself)

  • JDK 11 through 25 (required at runtime to launch the simulator or "Run as desktop app" target)

  • JDK 17 (required when compiling the Android port)

  • Apache Maven 3.6 or newer

  • macOS with Xcode (if you plan to build or test the iOS port)

Preparing the Maven workspace

Clone the repository and run the Maven aggregator from inside the maven subdirectory. This installs the complete SDK (core runtime, simulator, and ports) into your local Maven cache:

$ git clone https://github.com/codenameone/CodenameOne
$ cd CodenameOne/maven
$ mvn install

The default build runs every module and its unit tests. Append -DskipTests if you want to skip the test phases to speed up local builds.

The version printed by Maven will end with -SNAPSHOT when you build from the master branch. Published releases omit the suffix.

Installing the Maven archetypes

Codename One ships its project archetypes in a companion repository. Install them once so that mvn archetype:generate (and the Codename One Initializr) can reference your locally built SDK artifacts:

$ git clone https://github.com/shannah/cn1-maven-archetypes
$ cd cn1-maven-archetypes
$ mvn install

Running tests selectively

The Maven aggregator exposes modules for the different automated test suites. Run any of these from the CodenameOne/maven directory:

  • Core unit tests:

    $ mvn -pl core-unittests test

  • Integration tests (simulator and build client):

    $ mvn -pl tests -am verify

Refer to the READMEs in maven/core-unittests and maven/tests for more configuration flags, platform requirements, and environment variables.

Using your local build in application projects

After running the mvn install commands above, the Codename One artifacts are available in your local Maven repository. To consume that build in an application generated from the Codename One Initializr (or any other Maven project), adjust the pom.xml properties to reference your snapshot version:

<properties>
    <!-- Replace with the snapshot printed during mvn install -->
    <cn1.version>{cn1-snapshot-version}</cn1.version>
    <cn1.plugin.version>{cn1-snapshot-version}</cn1.plugin.version>
</properties>

Open the project in your IDE and build or run it. Maven will resolve the local snapshot instead of downloading the latest published release.

Why build from source

Building the SDK yourself gives you:

  • Immediate access to fixes and features before they reach a release.

  • The ability to inspect, debug, and change the framework when you need custom behavior.

Once you’re comfortable with the baseline build, continue with the scripts in scripts/ or the BUILDING.md guide to compile specific ports (Android or iOS) or to automate CI workflows.