Hello! I've got a problem with using XML beans (v. 2.2) as facts with shadow proxy turned on (Drools 4.0.7). I'm using a stateful session created by method newStatefulSession(java.io.InputStream stream). I have a base WorkingMemory instance with some predefined facts implemented as Apache XML beans. Then, I write it to an array of bytes using ByteArrayOutputStream and ObjectOutputStream in order to create ByteArrayInputStream and create new stateful session using the method mentioned above. Here is the fragment of my code: // --> BEGIN OF CODE FRAGMENT // This is just an initialization of an XML bean fact MyBean fact1 = MyBean.Factory.newInstance(); fact1.setField1("someText"); fact1.setField2(FieldType.Factory.newInstance()); // props contains some properties defined, but it doesn't matter RuleAgent ruleAgent = RuleAgent.newRuleAgent(props); RuleBase ruleBase = ruleAgent.getRuleBase(); // Here I create a base working memory instance WorkingMemory baseWm = ruleBase.newStatefulSession(false); // and insert the fact baseWm.insert(fact1); // Here I write a base working memory to a byte buffer ByteArrayOutputStream baos1 = new ByteArrayOutputStream(); ObjectOutputStream oos1 = new ObjectOutputStream(baos1); oos1.writeObject(baseWm); oos1.close(); byte[] buf1 = baos1.toByteArray(); // and create a new stateful session based on the buffer ByteArrayInputStream bais1 = new ByteArrayInputStream(buf1); StatefulSession session1 = ruleBase.newStatefulSession(bais1); // --> END OF CODE FRAGMENT When shadow proxies is turned off, everything works fine. I can fire rules and they see the fact. But when I turn the shadow proxies on, I've got an exception: java.io.NotSerializableException: org.example.myBean.MyBeanShadowProxy at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.writeArray(ObjectOutputStream.java:1251) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1075) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302) at java.util.HashMap.writeObject(HashMap.java:2336) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:917) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1339) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302) at com.sample.DroolsTest4.main(DroolsTest4.java:51) I've checked and MyBean class is serializable. It looks like the proxy of MyBean is not. What can be wrong here? Did I do any mistake? Everything is fine when I use ordinary beans, not XML beans. How the mechanism of creating shadow proxies work? Best regards! -- Przemysław Różycki IT Architect AMG.net, A Bull Group Company ul. Łąkowa 29 90-554 Łódź www.amg.net.pl