REST web services are also known as simple URL services, because they can be requested through the URL parameters with a simple GET HTTP method, which commonly gives as answer a plain-text JSON object. Like for example the Facebook and Twitter APIs. Here you can see how to do a REST web service using the Jersey RI with Eclipse, Maven and Tomcat.
Logs are a essential part of any serious application running in the production environment, because they can trace all the users and system actions, allowing if needed, find who did what and when, or why the application crashed as well. That's the Log4j2 library mission! Here you can see how use this library with Eclipse IDE and Maven.