title: Error Null pointer. (io.reactivex.Scheduler)' on a null object reference
body: <p>This is my log cat. When i click on specific tab, my app crashes.</p>
  
  <pre><code>java.lang.NullPointerException: Attempt to invoke virtual method 'io.reactivex.Flowable io.reactivex.Flowable.observeOn(io.reactivex.Scheduler)' on a null object reference
      at com.example.haji.Fragment.RecentFragment.loadRecents(RecentFragment.java:93)
      at com.example.haji.Fragment.RecentFragment.onCreateView(RecentFragment.java:86)
      at android.support.v4.app.Fragment.performCreateView(Fragment.java:2346)
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1428)
  </code></pre>
  
  <p>When i call loadRecents, it give me error. Please help.</p>
  
  <pre><code>private void loadRecents() {
      Disposable disposable = recentsRepository.getAllRecents().observeOn(AndroidSchedulers
          .mainThread()).subscribeOn(Schedulers.io()).subscribe(new Consumer &lt;List &lt;Recents&gt;&gt;() {
          @Override
          public void accept(List &lt;Recents&gt; recents) throws Exception {
              onGetAllRecentsSuccess(recents);
          }
      }, new Consumer &lt;Throwable&gt;() {
          @Override
          public void accept(Throwable throwable) throws Exception {
              Log.d("Error",throwable.getMessage());
          }
      });
      compositeDisposable.add(disposable);
  }
  </code></pre>