ok, figured out in my Jboss-as 7 cofiguration file (standalone-full.xml), in the datasource definition, I had not turned on the JTA flag on the JBPM datasource.
Now there is another question out of curiosity : Once my process has executed, I see a delete statement deleting the row from processinstanceinfo. My workflow is a simple HelloWorld workflow. My question is : does jBPM remove the data from ProcessInstanceInfo table once the processinstacne has run ?
127.0.0.1-8080-1) Hibernate: select processins0_.InstanceId as col_0_0_ from ProcessInstanceInfo processins0_ inner join EventTypes eventtypes1_ on processins0_.InstanceId=eventtypes1_.InstanceId where eventtypes1_.eventTypes=?
16:42:43,022 INFO [stdout] (http-localhost-127.0.0.1-8080-1) Hibernate: insert into SessionInfo (lastModificationDate, rulesByteArray, startDate, OPTLOCK, id) values (?, ?, ?, ?, ?)
16:42:43,106 INFO [stdout] (http-localhost-127.0.0.1-8080-1) Hibernate: update SessionInfo set lastModificationDate=?, rulesByteArray=?, startDate=?, OPTLOCK=? where id=? and OPTLOCK=?
16:42:43,115 INFO [stdout] (http-localhost-127.0.0.1-8080-1) Hibernate: insert into ProcessInstanceInfo (id, lastModificationDate, lastReadDate, processId, processInstanceByteArray, startDate, state, OPTLOCK, InstanceId) values (?, ?, ?, ?, ?, ?, ?, ?, ?)
16:42:43,129 INFO [stdout] (http-localhost-127.0.0.1-8080-1) Hibernate: delete from ProcessInstanceInfo where InstanceId=? and OPTLOCK=?