Regardless of the logging framework in use (logback, log4j, commons-logging, java.util.logging, ...), loggers should be:

Noncompliant Code Example

With a default regular expression of LOG(?:GER)?:

public Logger logger = LoggerFactory.getLogger(Foo.class);  // Noncompliant

Compliant Solution

private static final Logger LOGGER = LoggerFactory.getLogger(Foo.class);

Exceptions

Variables of type org.apache.maven.plugin.logging.Log are ignored.