java - Spring transaction in service and DAO layers -

in example have 1 hibernate entity , 1 dao.

@entity @table(name="myentity") public class myentity {      @id      @generatedvalue(strategy = generationtype.identity)     @column(name="id")     private long id;      @column(name="action")     private string actionname;  }  ...................  @repository("mydao") @transactional(propagation = propagation.required) public class mydao {      @autowired     private sessionfactory sessionfactory;      public void saveobject(myentity myentity){         sessionfactory.getcurrentsession().save(myentity);     }  } 

when use dao in service in such manner

@service("myservice") @transactional(propagation = propagation.required) public class myservice  {      @autowired     private mydao mydao;      public void executetransaction(){         myentity myentity = new myentity();          myentity.setactionname("action1");         mydao.saveobject(myentity);  //      myentity = new myentity();         myentity.setactionname("action2");         mydao.saveobject(myentity);     }  } 

only 1 row(action2) saved in database. when remove comment both rows(action1 , action2) saved(this behaviour need). question how transactional annotation on service layer influences on transaction(method executetransaction()) execution. why without transactional annotation on service layer both rows saved in database , last saved annotation?

without myentity = new myentity(); record in database updated, not inserted, because it's same entity. sugest set <property name="show_sql">true</property> in hibernate conf. show happening.