code: @Override
    public Object getProperty(final String name) throws OptionsException {
      Object val = getOptProperty(name);
  
      if (val == null) {
        throw new OptionsException("Missing property " + name);
      }
  
      return val;
    }
docs: Get required property, throw exception if absent
  
  @param name String property name
  @return Object value
  @throws OptionsException