docs: private SystemProperties loadConfiguration(String propertiesConfig, ServletContext context) throws IllegalStateException{
          InputStream inStream = null;
          try {
              inStream = getStreamForLocation(propertiesConfig, context);
              
              JAXBContext jaxb = JAXBContext.newInstance(SystemProperties.class.getPackage().getName());
              return (SystemProperties) jaxb.createUnmarshaller().unmarshal(inStream);
          } catch (FileNotFoundException e) {
             throw new IllegalStateException("Could not find configuration file: " + propertiesConfig, e);
          } catch (JAXBException e) {
              throw new IllegalStateException("Error while reading file: " + propertiesConfig, e);
          } finally {
              if (inStream != null) {
                  try {
                      inStream.close();
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
          }
      }