public void setLevel(String level) {
      try {
        LogManager.getRootLogger().setLevel(Level.toLevel(level));
      } catch (Exception e) {
        log.error("Unable to set level to: " + level, e);
      }
    }
An implementation of JmxLog4JMBean that calls getLevel and setLevel on the
root logger.
samza-log4j/src/main/java/org/apache/samza/logging/log4j/JmxAppender.java