Hello, After adding a few hundred rules, and with the same code, KnowledgeBase serialization has started to generate StackOverflowError. I have increased the VM stack size as a workaround, but I was hoping to implement something more robust. I specifically need to serialize the KnowledgeBase, and not the session. I'm using this code: private void dumpKnowledgeBase(String file, KnowledgeBase kbase) { try { FileOutputStream ostream = new FileOutputStream(file); DroolsObjectOutputStream p = new DroolsObjectOutputStream(ostream); p.writeObject(kbase); p.flush(); ostream.close(); } catch (Exception e) { System.err.println(e); e.printStackTrace(); System.err.println("Could not write knowledge base "+file); } } This is due to writeObject recursion? Any ideas? A.