code: @SuppressWarnings("unchecked")
    public <T> Class<T> getClass(String key)
        throws ClassNotFoundException {
      if (containsKey(key)) {
        return (Class<T>) Class.forName(get(key));
      } else {
        throw new IllegalArgumentException("Missing key " + key + ".");
      }
    }
docs: Gets the class value <code>key</code>.
  
  @param key key to get value for
  @param <T> return type
  @throws java.lang.IllegalArgumentException if the key is not found
  @throws java.lang.ClassNotFoundException if the class can't be found
  @return value