@SuppressWarnings("unchecked")
  public <T> Class<T> getClass(String k) {
    if (containsKey(k)) {
      try {
        return (Class<T>) Class.forName(get(k));
      } catch (Exception e) {
        throw new ConfigException("Unable to find class.", e);
      }
    } else {
      throw new ConfigException("Missing key " + k + ".");
    }
  }
Store and retrieve named, typed values as configuration for classes implementing this interface.
samza-api/src/main/java/org/apache/samza/config/Config.java