FF4J, stands as - Feature Flipping for Java -, implements the Feature Toggle agile development practice. It allows you to easily enable and disable features at runtime through dedicated console. Even if a feature is enabled, you can limit its usage to a subset of users through roles. You can finally defined your own strategy to decide if a feature is enabled based on custom context (e.g : the call me button should be available only during office hours 09:00-18:00 (full sample in documentation)
Read the documentation on the Wiki.
Got a real problem? Raise an issue.
[Run the demo] (http://ff4j-demo.octo-clu.cloudbees.net/)