Just to give a bit of background on what I am trying to achieve. I am trying to use the framework in a high performance application. eg more than 200 transactions per second. In order to achieve this I need to eliminate the need for a database in the backend of the framework and use a in memory solution. I do not want to use a database but a cache or the map solution is more acceptable. I used the map implementation above and it work for a few transactions but then after a little while for some signalEvents i start getting that error. I am not sure what it means but it seems like an issue setting a state (do know which state). I really need help on this.