Here is an example of using RxJava via the Couchbase Java SDK.

findByUserName.java

public Iterable<Playlist> findByUserName(String userName) {
  return getBucketFactory()
    .getAsyncBucket(Playlist.class)
    .flatMap(bucket -> bucket
      .get(USER_PREFIX + userName)
      .flatMap(doc -> 
        Observable.from(doc.content().getArray(PLAYLISTS_PROPERTY))
      )
      .flatMap(id -> bucket.get(id.toString()))
      .map(doc -> fromJsonObject(doc.content(), Playlist.class))
      .timeout(1, TimeUnit.SECONDS)
      .onErrorResumeNext(t -> 
        Observable.error(new RepositoryException(t))
      )
    )
    .toBlocking()
    .toIterable();
}