We recommend to move away from using System.out.println("Your message")
because using stdout is not the same as using stderr or a logging interface.
The reason you shouldn't use System.out is that we depend on output redirection
provided by ev3dev's brickrun. stderr is redirected via SSH to the user
when running remotely. If you use System.out, the message will be
displayed on the brick display only. On the other hand, this might
be intentional, in which case you should use System.out.
Also, to align with the best practises in the software industry, we integrated support for SLF4J (Simple Logging Facade for Java).
The Simple Logging Facade for Java (SLF4J) serves as a simple facade or abstraction for various logging frameworks (e.g. java.util.logging, logback, log4j) allowing the end user to plug in the desired logging framework at deployment time.
The library uses SLF4J in the whole project, but the user has to choose the final implementation. In the example, the development uses Logback but users can choose any other compatible logging framework.
For testing purposes, enabling traces is a good practice, but for production builds you might want to disable some levels. Generating too many tracing output creates a measurable impact on the program performance.
https://javarevisited.blogspot.com/2016/06/why-use-log4j-logging-vs.html https://www.slf4j.org/ https://logback.qos.ch/