Hello, In our environment we need to develop a framework wherein we would have about a dozen rule templates whose data will be provided by users using spreadsheets. Basically users will upload excel workbooks containing 10-12 worksheets and we'll be using ExternalSpreadsheetCompiler to generate the appropriate DRLs that will then be 'add'ed to a KnowledgeBuilder class to create a KnowledgeBase. We need to provide this capability use a web application deployed in Tomcat. Question - Are KnowledgeBuilder/ExternalSpreadSheetCompiler thread safe ? Is it safe to develop this KnowledegeBase build process in a web application ? If these classes are not thread safe, can someone please advise me on how to make this framework single threaded ? It's perfectly acceptable for the framework to be single threaded (essentially if more than a single session tries to upload a workbook, they will have to wait a few mins if there are other workbooks being processed ahead of theirs). I know the last question is not drools centric, but it would be great to hear from the gurus on how best I can make the build/compile process single threaded. Please let me know if this is a safe approach to take or if there are ways to make this approach safe ! Thanks in advance, -G -- View this message in context: http://drools.46999.n3.nabble.com/Is-it-safe-to-build-a-knowledgebase-com... Sent from the Drools: User forum mailing list archive at Nabble.com.