Hi, I am developing a web service that evaluates risks on a certain fact, I accumulate the risks in the working memory (stateless working memory), but i need to return the asserted risks from the web service the web method signature is like public Risks assertFact(Fact fact) where Risks: factId Risk[] The operation of insertion of a fact into the working memory is thread safe (there is a lock object invoked in the execute or insert operation). I need to know if i called workingMemory.executeWithResults() and getting the global variable , are these results thread safe ? public Risks assertFact(Fact fact){ ... synchronized(workingMemory){ StatelessSessionResult result = workingMemory.executeWithResults(fact); risks = result.getGlobal("xyz"); } ... return risks } it would be better to remove the synchronized block , but I don't know if this is okay or not. Thanks in advance. Best regards, -- Waleed Zedan