Please read the CONTRIBUTING.md first. The most important parts regarding the actual entry:

- Write about it's unique selling point compared to other projects.
- If it's a commercial project, then mark it as such, e.g. `[Title ![c]](URL)`.
- Ensure that you provide concise and informative descriptions.
- Do not use a description like "A library/project/tool/framework for JSON processing in Java" since all of this is implied.
- Finish the description with a dot.
- Try to order it alphabetically.