code: public static String initializeLogging() throws IOException {
          System.setProperty("org.slf4j.simpleLogger.logFile", "System.out");
          System.setProperty("org.slf4j.simpleLogger.showDateTime", "true");
          System.setProperty("org.slf4j.simpleLogger.dateTimeFormat", "yyyyMMdd.HH:mm:ss.SSS");
          // Peek at mdw.yaml to find default logging level, but do not initialize PropertyManager
          // which could initialize slf4j prematurely.  (Works only with yaml config file).
          String mdwLogLevel = null;
          File mdwYaml = getConfigurationFile("mdw.yaml");
          if (mdwYaml.exists()) {
              YamlProperties yamlProps = new YamlProperties("mdw", mdwYaml);
              mdwLogLevel = yamlProps.getString("mdw.logging.level");
              if (mdwLogLevel != null) {
                  if (mdwLogLevel.equals("MDW_DEBUG"))
                      mdwLogLevel = "TRACE";
                  System.setProperty("org.slf4j.simpleLogger.log.com.centurylink.mdw", mdwLogLevel.toLowerCase());
              }
          }
          return mdwLogLevel;
      }
docs: For Spring Boot with slf4j SimpleLogger, an opportunity to initialize logging before Spring starts logging.
  Otherwise for slf4j, properties have already been defaulted before we have a chance to set them.
  
  See mdw-spring-boot AutoConfig for initialization of logback for pure Spring Boot apps.