Hello people, this is my first thread here, so I apologize for whathever I miss. I'm working on a threat detection engine, based on Drools 3.0.5 The rule structure (written in XML) is something like this: <rule name="SWL1_d0e32"> <lhs> <column identifier="vulnObject" object-type="SoftwareElement"> <literal field-name="name" evaluator="matches" value=".*?Firefox"/> <literal field-name="version" evaluator="==" value="0.8"/> </column> </lhs> <rhs>assert ( new SoftwareThreat ( vulnObject, SoftwareThreat.HIGH_RISK, SoftwareThreat.LOW_RISK , SoftwareThreat.LOW_RISK ));</rhs> </rule> Well, the problem is: serializing a rulebase with more than 30000 rules like this. This is the code: PackageBuilderConfiguration conf = new PackageBuilderConfiguration(); conf.setJavaLanguageLevel( "1.5" ); PackageBuilder builder = new PackageBuilder( conf ); Reader source = new InputStreamReader( DroolsCIMAPI.class.getResourceAsStream( "/DroolsRuleset_TEST32000.xml" ) ); try { builder.addPackageFromXml( source ); Package pkg = builder.getPackage(); FileOutputStream tempFile = new FileOutputStream("./SWL1_package_TEST.bin"); ObjectOutput oos = new ObjectOutputStream(tempFile); pkg.writeExternal(oos); oos.flush(); oos.close(); tempFile.flush(); tempFile.close(); } catch (DroolsParserException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } Actually the serialization works for relatively "small" rulesets (<20000, increasing max heapsize to 256m)... But when using rulesets over 30000 rules (eg. this sample test) the process hangs exactly in "pkg.writeExternal(oos)" filling up the cpu to 100%... without writing, obviously. I checked the filesize of every serialized pakage (smaller), seeing that they are always under 50Mb. A note: without serialization, everything works fine. Maybe a 50Mb limit somewere? Maybe I'm the newbest Drools user ever? :) Thanks in advance. Fabio, Politecnico di Torino Italy