title: JPA Hibernate updates an entity but there are no any changes in the DB
body: <p>In short, I have three methods:</p>
  
  <pre><code>    @Transactional(propagation=Propagation.REQUIRED, noRollbackFor=Exception.class)
      public void Manage(long bookId) throws Exception {
  
          Book book = dao.getByKey(bookId);
  
          //...
  
          register(book);
  
      }
  
  
      @Transactional(propagation=Propagation.REQUIRED, noRollbackFor=Exception.class)
      public void register(Book book) {
  
          try {
  
              // updateSomeId method should be called in another thread
              // POST request to the service, waiting for the response then updating the DB
              Runnable task = () -&gt; {
  
                  if(someId &gt; 0) {
                      dao.updateSomeId(book, someId);
  
              }
              Thread thread = new Thread(task);
              thread.start();
          } catch (Exception e) {
  
          }
  
      }
  
  
  
      @Transactional(propagation=Propagation.REQUIRED, noRollbackFor=Exception.class)
      public void updateSomeId(Book book, long someId) {
          try {
              Book findedBook = getByKey(book.getBookId());
              findedBook.setSomeId(someId);
          } catch (Exception e) {
              logger.error("error", e);
          }
      }
  </code></pre>
  
  <p><code>updateSomeId</code> method must update the <code>someId</code> property in Book table.<br>
  In the log I see:
  <code>Hibernate: update Book set author=?, someId=? where bookId=?</code></p>
  
  <p>But, there are no any changes in my DB, no any errors. Could anyone explain what happens and how to solve it?
  <strong>It's one of thousands of updates I have and only in this case it hasn't updated the DB table.</strong></p>
  
  <p><strong>JPA 2.1</strong></p>
  
  <p><strong>Hibernate 5.2.10.Final</strong></p>