Logging is done via logback. Logback bootstrap and configuration is described in detail here.
You will usually find the logback.xml file inside the conf directory. Also, you can define a logback.xml file per application.env by appending the env. See some examples:
logback.uat.xmlwhenapplication.env = uatlogback.prod.xmlwhenapplication.env = prod
If the logback[.env].xml file isn't present, logback.xml will be used as a fallback.