Add Log4J2 configuration instructions for Gradle-based projects

[behrangs-sportsbet]

Looks like Log4J2 configuration instructions for Gradle-based projects is not given in the docs.

I usually exclude spring-boot-starter-logging from all my configurations using this code snippet:

configurations {
    all {
        exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
    }
}

and then explicitly add a dependency on org.springframework.boot:spring-boot-starter-log4j2 to switch to Log4J2.

The docs should be updated with instructions outlining these steps.

I can create a PR with the changes, but is this the recommended approach to setup Spring Boot with Log4J2 in a Gradle-based project?

[snicoll]

@behrangs-sportsbet there is a dedicated section but, granted, only covers Maven. I am not entirely sure that what you've described is the recommended way with Gradle but I am sure @wilkinsona knows.

[wilkinsona]

I don't think there is a recommended way to do this with Gradle. There's more than one way to do it and which one is best is, largely, down to personal preference. That said, the approach shown above is probably the most robust way to do it so is probably the right one to document. Anyone who knows Gradle well enough to have a different preference will also know how to configure it.

[behrangs-sportsbet]

@wilkinsona will create a PR later today to amend the docs with the instructions.