static private Level initVerbosity() {
        String verbosityStr = System.getProperty(SLF4J_INTERNAL_VERBOSITY_KEY);

        if(verbosityStr == null || verbosityStr.isEmpty()) {
            return Level.INFO;
        }

        if(verbosityStr.equalsIgnoreCase("DEBUG")) {
            return Level.DEBUG;
        }

        if(verbosityStr.equalsIgnoreCase("ERROR")) {
            return Level.ERROR;
        }


        if(verbosityStr.equalsIgnoreCase("WARN")) {
            return Level.WARN;
        }

        // anything else including verbosityStr.equalsIgnoreCase("INFO")
        return Level.INFO;
    }
This system property controls the internal level of chattiness
of SLF4J. Recognized settings are "INFO", "WARN" and "ERROR". The default value is "INFO".
slf4j-api/src/main/java/org/slf4j/helpers/Reporter.java