title: Spring @Transactional method called by multithread(multi-request)
body: <p>Java web<br>
  Spring MVC framework</p>
  
  <p>In my service level, I wrote a <code>@Transactional</code> method. In that method, I update some data in database and then read the data from the database later.
  What surprises me is that when several requests come, inside the same thread, the data change is visible(which is supposed to be), but the data change is not visible in other thread.<br>
  Isn't different threads of one method build as one transaction?<br>
  And what should I do if I still want to use transaction and I want the same method called in different threads be in one transaction (the change of the data can be seen by each other)?</p>