Book teaching how to write modern and effective Java. It is maintained by the community, anyone can contribute.
Feel free to join our discord server
if you have any questions, or require assistance with the project.
Please read Contributing guidelines if you are considering helping us out! There you will find a detailed guide on how to contribute, and plenty of resources in case this is your first time submitting a PR to an open-source project.
Head over to the Wiki as general entry point to the project. It provides lots of tutorials, documentation and other information.