How to import ImmutableMap in quick start?

[liu brent]

Hi,
  In http://incubator.apache.org/kafka/quickstart.html, there is a line:
   Map<String, List<KafkaMessageStream<Message>>> topicMessageStreams =
connector.createMessageStreams(ImmutableMap.of("test", 4));
  But I do not know how to import ImmutableMap. Do we need to a package?

Thanks,
Brent