code: public InputStream getBuilderXML() throws IOException {
          return builderXMLPath == null ?
              Configuration.class.getResourceAsStream(DEFAULT_BUILDER_XML) :
              DocFile.createFileForInput(this, builderXMLPath).openInputStream();
      }
docs: Return the input stream to the builder XML.
  
  @return the input steam to the builder XML.
  @throws FileNotFoundException when the given XML file cannot be found.