Hi, i'm new to drools so excuse me if i'm asking newbie question. For a project I insert via rest service a list of object to drools server, in a stateless session - no need to use a stateful session. The rules are fired and new objects are inserted. ex : rule "1" when $c : condition() then insert(new FiredRule("my rule 1 fired", $c)) end I also have a query who gets all the FiredRule query "get fired rules" firedRule : FiredRule() end My problem is that i can't get results from query when i'm in stateless mode. It works in stateful mode, but I need drools to work only with object I send via rest service at time t. I don't want them store in in the knowledge base and be reused for a future request. I'm block here. I send via json the batch-execution command with "insert-elements" and "query" => "name":"get fired rules","out-identifier":"rules" and I have an Exception when I set an out-identifier to "fire-all-rules" 11:26:00,552 ERROR [DefaultErrorHandler] Failed delivery for exchangeId: 949a5873-d146-4ad3-bc9c-d0dd9f7bbc81. Exhausted after delivery attempt: 1 caught: java.lang.NullPointerException java.lang.NullPointerException at org.drools.command.runtime.rule.FireAllRulesCommand.execute(FireAllRulesCommand.java:110) at org.drools.command.runtime.rule.FireAllRulesCommand.execute(FireAllRulesCommand.java:32) at org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:155) at org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:76) at org.drools.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:265) at org.drools.camel.component.DroolsExecuteProducer.process(DroolsExecuteProducer.java:100) When I test my case with java, I can get my query results, so I am led to think that it is a problem on server side, maybe jars in the lib??? Or is it impossible to set an out-identifier for fire-all-rules in stateless mode?. Another consideration were to dispose each knowledgesession (on stateful mode) when I send request to drools, but there is no command to do that, only stop/restart server??? Subsidiary question : is it possible to add a System.out.println() in my query??If yes, how to do it? Thank you for your help JC -- View this message in context: http://drools.46999.n3.nabble.com/Drools-server-get-a-query-result-tp3512... Sent from the Drools: User forum mailing list archive at Nabble.com.