Executor.excute might need to work in separate thread

[jamoore]

When an @Transactional doWork() method is inside of another @Transactional call, the Hibernate session can get confused about saving or not saving Event objects (error: ProperyValueAccess exception on Event.containingEvent)

Post #1158, this caused IShare.createShare() to break since it calls into @Transactional(readOnly=false) SessionManager methods.

[jmoore]

r3452 has an initial workaround.

[jmoore]

See also r3631

[jmoore]

r3789 contains an improved implementation with ExecutorService.submit(Callable). The idiom is:

  Future<Long> future = executor.submit(new Callable<Long>(){
     return new Long(1L);
  }
  // Some time later
  Long long = executor.get(future);

See #1201 for another concrete usage.