code: public void reset() {
          checkPermission();
          synchronized (this) {
              props = new Hashtable<>();
              // Since we are doing a reset we no longer want to initialize
              // the global handlers, if they haven't been initialized yet.
              initializedGlobalHandlers = true;
          }
          for (LoggerContext cx : contexts()) {
              Enumeration<String> enum_ = cx.getLoggerNames();
              while (enum_.hasMoreElements()) {
                  String name = enum_.nextElement();
                  Logger logger = cx.findLogger(name);
                  if (logger != null) {
                      resetLogger(logger);
                  }
              }
          }
      }
docs: Reset the logging configuration.
  <p>
  For all named loggers, the reset operation removes and closes
  all Handlers and (except for the root logger) sets the level
  to null.  The root logger's level is set to Level.INFO.
  
  @exception  SecurityException  if a security manager exists and if
  the caller does not have LoggingPermission("control").