You can use the code from these repositories to experiment, test, build, create patches, issue pull requests, etc.
https://github.com/eclipse-ee4j/enterprise-deployment - Project repository hosted on GitHub.
https://github.com/eclipse-ee4j/jaxr-api - Project repository hosted on GitHub.
https://github.com/eclipse-ee4j/jax-rpc-api - Project repository hosted on GitHub.
https://github.com/eclipse-ee4j/management-api - Project repository hosted on GitHub.