anonymous wrote : | ... can you elaborate? | Let's take a different angle: This is not about the process definition language. (It's going to be pluggable anyway, right?) Building an API doesn't necessarily mean throwing away what's there, it could as well mean refactoring the existing one. The API will have core elements and terminology. Each core elements has associated semantics which lead to implementation detail. We want the API to be correct, easy to use and easy to learn. The process of finding these core elements (or core concepts) and establishing names for them is important to get one step closer to 'correctness'. The well known list of 'basic concepts', which Thomas suggested, is merely a collection of core elements that will lead to both a meaningful set of API that can represent of large number of use cases to begin with, but at the same time covers critical areas of the engine implementation. At least that's the idea. If the list is incomplete or the terminology is somehow misleading then make suggestions how it could be changed. Again this doesn't necessarily mean we ditch the existing jBPM4 code base, it's merely a process of verification. If the current code base would already have a precise and 'to the point' API, then we wouldn't need to do it. Here's how I can picture the meeting: We go through the list of core elements and for each of those we'll first discuss correctness and importance of that element in a BPM world and then secondly match it with jBPM4 elements. Either the BPMN expression is wrong to begin with or unnecessary for jBPM4 (no use case) then we can ditch it right away. But if it turns out to be important then it will either have a representation in jBPM4, just differently named or it requires changes to the code base. But we'll start with a small set, and then gradually increase to the API until it is feature complete. In the beginning, the API would allow you todo everything jBPM4 is currently capable of, but sooner or later it will. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4180960#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...