Reading log file from other container by logstash

There is a java application running in a container which created by other team and I am new to docker. a logstash container need to install and then config it for reading logs from java application docker container.

i need to use old version of of logstash 3.0. should I create a image with logstash or container without logstash then download logstash?

configuration for logstash configureation should be in docker or should be in data vol. Docker is stateless so configuration should be outside?