title: How to write documentation for observable return which throws exceptions in RxJava
body: <p>Not sure how to document throws declaration in Java doc style. Below example:</p>
  
  <pre><code>/**
   * Get Facebook Friends
   *
   * @param facebookToken - Facebook Token
   * @return list of {@link User}
   * @throws SomeCheckedException &lt;- this is normally the way, but not for Observable return type
   */
  
  public Observable&lt;List&lt;User&gt;&gt; getFriends(String facebookToken) {
      return get("/me/friends", facebookToken)
          .flatMap(response -&gt; {
              FacebookResponse facebookResponse = response.readEntity(FacebookResponse.class);
  
              if (null != facebookResponse.getError()) {
                  return Observable.error(parseException(facebookResponse.getError()));
              } else if (null == facebookResponse.getData()) {
                  return Observable.error(new FacebookException("Empty data"));
              }
  
              return Observable.just(facebookResponse.getData());
          });
      }
  </code></pre>
  
  <p>The method is supposed to return <code>Observable.error()</code>, and I want to developer who is gonna call this method know about possibly exception do be handled in <code>onErrorNextResume</code>, etc.</p>
  
  <p><a href="http://docs.oracle.com/javase/8/docs/technotes/tools/windows/javadoc.html" rel="nofollow noreferrer">Docs</a> don't cover anything similar.</p>