"jbarrez" wrote : -> This could lead to castings of executions to ProcessInstances, which aren't process instances (ie no root execution). But for the compiler, nothing is wrong since they are exactly the same... | i don't see the need for those casts. first, the api returns process instances where appropriate. secondly, process instance doesn't add any methods, so there will be no reason to cast :-) the thing that i'm mostly in doubt about is the return value of the signal methods. previously we returned the execution in which the signal was given. but in the context of this thread it looks to me more logically that we return the process instance. that could lead to confusion, but if we introduce the ProcessInstance interface, it becomes clear that the process instance is returned. so on balance i am in favour of introducing ProcessInstance and changing the return value of the signal methods to ProcessInstance View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4225890#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...