code: static String getValue(String key) {
          String result = StringUtils.defaultIfBlank(System.getProperty(key), StringUtils.EMPTY);
          result = StringUtils.defaultIfBlank(result, System.getenv(key));
          return result;
      }
docs: Gets a configured value for the given key from either the system
  properties or an environment variable.
  
  @param key The name of the configuration value.
  @return The system property corresponding to the given key (e.g.
  -Dkey=value). If that is blank, the environment variable
  corresponding to the given key (e.g. EXPORT key=value). If that
  is blank, {@link StringUtils#EMPTY}.