title: Flush saveAll in JpaRepository
body: <p>Since there's a <code>saveAndFlush()</code>, is there a way to 
  Flush the updated entities when using <code>saveAll()</code>?</p>
  
  <p>I'm trying to update entities by batch.</p>
  
  <p>Will really be a big help!</p>
  
  <p>Thank you!</p>