Java Maven project - Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 90 seconds of launch
The reason it doesn't work is because you've configured it as web. Since your program isn't a webapp, you need to configure it as a worker process in the Procfile instead. Take a look at https://devcenter.heroku.com/articles/run-non-web-java-processes-on-heroku
You can try the following Procfile which should work:
worker: java -jar target/*.jar