code: void configurePort(String port) {
  
          if (StringUtils.isNotBlank(port)) {
              try {
                  this.port = Integer.parseInt(port);
                  log.info("Using port {}", this.port);
              } catch (NumberFormatException e) {
                  log.info("Unable to parse server PORT variable ({}). Defaulting to port {}", port, this.port);
              }
          }
      }
docs: Configures the server port by attempting to parse the given parameter,
  but failing gracefully if that doesn't work out.
  
  @param port The value of the {@value #PORT} parameter.