title: Convert Observable to Collection in RxJava
body: <p>I want to collect every item emitted in a Collection. I'm doing it this way:</p>
  
  <pre><code>List found = new ArrayList();
  controller.search(query)
            .doOnCompleted(new Action0() {
              @Override
              public void call() {
                  //Do something with "found" list
              }
          }).subscribe(new Action1&lt;String&gt;() {
              @Override
              public void call(String item) {
                  found.add(item);
              }
          });
  </code></pre>
  
  <p>Is there a RxJava built-in way to carry this out?</p>