It would be nice to have up to date library not using deprecated code, because:
Brave v. 4 allows you to use brave.Tracing so one can easily register https://github.com/openzipkin/brave/tree/master/context/slf4j which allows you to have in each log line info about spans:
Then it is easy to copy and use span id to zipkin UI in case of debugging. (btw currently there is Long value of span instead of Hexadecimal printed).
There is possibility to overlap with version 3 and 4 -> https://github.com/openzipkin/brave/tree/master/brave#upgrading-from-brave-3 so this could be good start.
Also brave.sampler.Sampler should be used in stead of com.github.kristofa.brave.Sampler