code: public void createDocumentClassificationFactory(
        final TrainingParameters params) throws IOException {
      final String featureDescription = DocumentFeatureDescriptor
          .createDocumentFeatureDescriptor(params);
      System.err.println(featureDescription);
      final byte[] featureGeneratorBytes = featureDescription
          .getBytes(Charset.forName("UTF-8"));
      final Map<String, Object> resources = DocumentModelResources
          .loadDocumentResources(params);
      //TODO add default feature generator
      setDocumentClassifierFactory(
          DocumentClassifierFactory.create(DocumentClassifierFactory.class.getName(),
              featureGeneratorBytes, resources));
    }
docs: Create {@code createDocumentClassificationFactory} .
  
  @param params
  the parameter training file
  @throws IOException
  if io error