Have you checked updated documentation?
I had the same problem, I was using version 8 of netbeans, I had to update to Apache Netbeans IDE version 12.4 and the problem was solved, I was able to open the traccar 4.13 project, and compile in the jar file without problems.
Thanks, updating for Apache Netbeans IDE version 12.4 it was possible to open the source code
Hello Anton, sorry for my ignorance, but since the last update to version 4.13 I can't open source code in NetBeans anymore.
It seems to me that this time there is no longer a pom.xml file in the source code.
I'm new to Java and I have no idea why this file doesn't exist at the moment, in previous versions of the source code it did.
I'm very grateful if you can explain to me.