CMP EJBs prevent concurrent access ?

[klemzer]

I have a servlet which does two things :

1- Create a new instance of an EJB x
2- findAll() the EJB x
3- show the EJB content in the resulting HTML

(so, basically : add an item to a list, find all the items in the list)

The EJB is CMP.

I open my browser and call the servlet. Everything works as expected.

Now, I hit the refresh button a lot of times so to add plenty of items and stress the system a bit.

Now and then, I got an excpetion telling me that concurrent access to the EJB are not allowed. I guess it's because sometimes I use the "getter" method of bean instance that is being created.

I really don't understand why that happens (I've read a lot and it seems that the container should do the proper serialization for me) and I don't know what to do to fix that.

Can someone help me ? Or better, direct me to the proper documentation I have to read to understand that better ?

Thank you

Stefan

[klemzer]

I think I have found my mistake.

In the servlet, I had a reference (instance variable) to a stateful session bean. In the doPost/doGet method, I was accessing that bean (bean.getBlabla()). So when I was hitting my refresh button, the servlet doPost/doGet was called concurrently and therefore, the bean.getBlabla() was called concurrently as well. That is forbidden, as explained in section 7.5.6 of EJB 2.0 specification.

Stefan