Ed, Tom, Yes, I do think it is a problem. In nearly any real-life application the process definition has to be accessed from many threads, each working with own process instance. For simplicity lets assume that they are all based on the same process definition. All process instances are on the different stages of the process. As soon as you send signal to the process instance JBPM will try to access the corresponding process definition internally. Process definition will have to read some additional data from the database using Hibernate session it was attached to. With multiple process instances processed in different threads there will be sooner or later the situation when the same hibernate session will be used to read different parts (or even the same part) of the process definition in the 2 or more threads . I think it is clear that it is not feasible to sync. all the accesses to the process instances. In my case I wrote some generic code that initializes recursively all the associations of the process definition whenever new process definition is loaded for the first time. I just didn't want to modify JBPM hbm files. But I do not see the reason to have lazy loading for the process definition, considering the problems it causes. At least for the cases that I would consider as a mainstream: few process definitions and many process instances (each instance requiring some part of the process definition for further processing). Andrey. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4042429#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...