Thanks Selaron for the test case. I will run it soon. For the moment, i try to use org.apache.commons.lang3.SerializationUtils to serialize an entity in a simple test case and the lazy load works fine.
it seems that there may be other causes for LazyInitiliazationException as mentionned in this blog
http://ankursinghal86.blogspot.com/2014/08/hibernates-and-lazyinitializationexcept.html
@Hibernate team : Maybe it's time to summarize all the cases that can cause this exception.