Hi Siddhartha,
See this blog for more info:http://blog.athico.com/2008/05/efficient-binary-protocol-marshalling.html
"The DefaultMarshalling class uses the Identity strategy if it is not passed a strategy factory."
Identity strategy is stateful. This means that the same instance needs to be used for deserialization.
You may try the Serialised strategy - SerializablePlaceholderResolverStrategy. However, with this strategy the fact identities change when you deserialize. That may or may not be a problem, depending on what you are doing.
Best Regards,
Michal

On Mon, Nov 3, 2008 at 9:06 PM, siddhartha banik <siddhartha.banik@gmail.com> wrote:
Hi Drools Team,
 
I am trying out new Serialization technique introduced in Drools 5.0 using "org.drools.marshalling.DefaultMarshaller".
 
The use case I am trying, is:
                                      Create a Stateful session.
                                      Then Serialize that.
                                      Try to load the the serialized session back.
 
Loading of serialized session is working good if, I try that in same java program & same object of DefaultMarshaller is used during serialization & de serialization of the Stateful session.
 
But, when I tried a different instance of DefaultMarshaller to read back the saved session, that is not working anymore. I am getting a exception :
 
java.lang.NullPointerException
 at org.drools.common.DefaultFactHandle.<init>(DefaultFactHandle.java:78)

 at org.drools.marshalling.InputMarshaller.readFactHandle(InputMarshaller.java:331)
 at org.drools.marshalling.InputMarshaller.readFactHandles(InputMarshaller.java:277)
 at org.drools.marshalling.InputMarshaller.readSession(InputMarshaller.java:179)
 at org.drools.marshalling.DefaultMarshaller.read(DefaultMarshaller.java:58)
 at org.drools.marshalling.DefaultMarshaller.read(DefaultMarshaller.java:15)
 at org.drools.reteoo.ReteooRuleBase.readStatefulSession(ReteooRuleBase.java:277)
 at org.drools.common.AbstractRuleBase.readStatefulSession(AbstractRuleBase.java:321)
 at com.sample.test.NewMarshallingTest.testSerializationInFile_1(NewMarshallingTest.java:79)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 at java.lang.reflect.Method.invoke(Unknown Source)
 at junit.framework.TestCase.runTest(TestCase.java:154)
 at junit.framework.TestCase.runBare(TestCase.java:127)
 at junit.framework.TestResult$1.protect(TestResult.java:106)
 at junit.framework.TestResult.runProtected(TestResult.java:124)
 at junit.framework.TestResult.run(TestResult.java:109)
 at junit.framework.TestCase.run(TestCase.java:118)
 at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)
 
With Drools 4.0.7 ... I can serialize a Stateful session & at later point of time I can deserialize that back. For our usecase, the feature is very critical.
 
Does Drools 5.0 support that ?  DefaultMarshaller is not serializable. So once a  Stateful session is serialized. At Later point of time, I am not able to read that back.
 
I have attached my test files.
 

Best Regards!
Siddhartha


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