code: private void validatePathExists(String[] paths, String optType) throws FileNotFoundException {
          for (String path : paths) {
              validatePathExists(path, optType);
          }
      }
docs: Validates whether or not the path(s) points at a file that exists; if the
  path(s) does not point to an existing file a FileNotFoundException is
  thrown.
  
  @param paths the paths to validate if they exists
  @param optType the option being validated (e.g. scan, out, etc.)
  @throws FileNotFoundException is thrown if one of the paths being
  validated does not exist.