System loggers run with level ALL --------------------------------- Key: LOGMGR-260 URL: https://issues.jboss.org/browse/LOGMGR-260 Project: JBoss Log Manager Issue Type: Bug Components: core Environment: Java 9+ Reporter: Philippe Marschall Priority: Major After migrating to Java 11 we were suddenly seeing a lot of caught exceptions {{sun.rmi.runtime.Log#getSource()}}. This was surprising to use because we WildFly which sets the "sun.rmi" logger to level WARN. Upon closer inspection the issue is that the logger used by {{sun.rmi.runtime.Log}} has level ALL ({{Integer#MIN_VALUE}}). The issue for this seems to be the following: # since Java 9 java.util.logging differentiates between system loggers (used by modules in the platform classloader) and user loggers (everything else), see {{java.util.logging#Logger.demandLogger(String, String, Class<?>)}} # when a system logger is created a second user logger is created and their configurations are merged, however they are merged based on internal state maintained by {{#setLevel(Level)}}, see {{java.util.logging.LogManager#demandSystemLogger(String, String, Module)}} and {{java.util.logging.Logger#mergeWithSystemLogger(Logger)}} # {{org.jboss.logmanager.Logger}} only ends up calling {{#setLevel(Level)}} with {{Level.ALL}} therefore the resulting system logger always has the level ALL The issue is quite hard to test because: # the effect only happens when the caller of {{#getLoggger(String)}} is a system module # the log output is not different, only {{#isLoggable(Level)}} checks that shouldn't succeed suddenly succeed so you only see the overhead