code: protected InputStream open()
      {
      try
        {
        if( getType() == null)
          {
          throw new IllegalStateException( String.format( "Unknown type for %s", this));
          }
  
        URL location = getLocation();
      
        return
          location == null
          ? System.in
          : (stream_ = location.openStream());
        }
      catch( Exception e)
        {
        throw new IllegalStateException( String.format( "Can't read %s", this), e);
        }
      }
docs: Opens a stream to read the contents of this resource.