code: static Converter createDefaultConverter() {
          List<NodeFactory> factories;
          String property = System.getProperty(LIBRARIES_PROPERTY_NAME);
  
          if (property != null && property.trim().length() > 0) {
              factories = createFactoriesSpecifiedInProperty(property);
          } else {
              factories = createDefaultFactories();
          }
  
          if (factories.isEmpty()) {
              throw new IllegalStateException("Please add either json.org, Jackson 1.x, Jackson 2.x or Gson to the classpath");
          }
          return new Converter(factories);
      }
docs: Creates converter based on the libraries on the classpath.