code: public static URI stringAsURI(String s) throws IOException {
      URI u = null;
      // try to make a URI
      try {
        u = new URI(s);
      } catch (URISyntaxException e){
        LOG.error("Syntax error in URI " + s
            + ". Please check hdfs configuration.", e);
      }
  
      // if URI is null or scheme is undefined, then assume it's file://
      if(u == null || u.getScheme() == null){
        LOG.warn("Path " + s + " should be specified as a URI "
            + "in configuration files. Please update hdfs configuration.");
        u = fileAsURI(new File(s));
      }
      return u;
    }
docs: Interprets the passed string as a URI. In case of error it
  assumes the specified string is a file.
  
  @param s the string to interpret
  @return the resulting URI
  @throws IOException