Not sure what happened with this post yesterday, another chain got started with it, so trying again. I have the application setup where the drl is generated from the database and then written to the file system. So far i have been working with the drl's without any problems but have run into issues while working with packages. Any help is much appreciated. Thanks. Here is what i am doing while serializing the package. PackageBuilder builder = new PackageBuilder(); builder.addPackageFromDrl(new StringReader(drl)); Package pkg = builder.getPackage(); DroolsStreamUtils.streamOut(new ObjectOutputStream(new FileOutputStream(new File(fileName+".pkg"))), pkg); i also tried the writeExternal on package, this genereate the file but got a class cast exception while trying to load it. The pkg file is generated and i dont think it has a problem unless i am missing something in the above code. Now, on the other side i am using drools-spring which sets up the agent on startup. I was doing some trial and error and found two configurations that worked but needed ResourceFactory.getResourceChangeScannerService().start(); ResourceFactory.getResourceChangeNotifierService().start(); to be in code, just the spring configuration didnt work (again if i am missing something please let me know). here are the spring configuration First <drools:kagent id="agent" kbase="base" new-instance="true"/> <drools:kbase id="base"> <drools:resources> <!--drools:resource type="DRL" source="file:C:\file.drl"/--> //this works <drools:resource type="PKG" source="file:C:\file.pkg"/> </drools:resources> </drools:kbase--> Second <drools:kagent id="agent" kbase="base" new-instance="true"> <drools:resources> <drools:resource type="CHANGE_SET" source="file:C:\change-set.xml"/> </drools:resources> </drools:kagent> <drools:kbase id="base"></drools:kbase> and the changeset <change-set...> <add> <resource source='file:/C:/file.pkg' type='PKG'/> </add> </change-set> -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/OptionalDataException... Sent from the Drools - User mailing list archive at Nabble.com.