WebLogic 6.1 SP2 stateful EJB handle serialization problem

Question

I try to serialize and later deserialize the handle of a stateful
session bean in WebLogic 6.1 SP2. This works on the client, but not on
the server. In WebLogic 6.1 SP1, it worked on both server and client.
The test code:
try {
InitialContext context = new InitialContext();
InfSessionHome sessionHome = (InfSessionHome)
InfEJBUtil.getInfEJBHome
(context, InfJNDINames.INFSESSION_EJBHOME,
InfSessionHome.class);
infSession1 = sessionHome.create();
// serialize
ObjectOutputStream objector = new ObjectOutputStream(byteStream);
objector.writeObject(infSession1.getHandle());
objector.flush();
objector.close();
byte[] ejbKeyBytes = byteStream.toByteArray();
// deserialize
ByteArrayInputStream byteInStream = new
ByteArrayInputStream(ejbKeyBytes);
ObjectInputStream objStream = new ObjectInputStream(byteInStream);
Handle ejbHandle = (Handle) objStream.readObject();
objStream.close();
InfSession infSession2 = (InfSession) ejbHandle.getEJBObject();
if (!infSession2.equals(infSession1)) {
throw new IllegalStateException("not equal: " + infSession2);
} catch (Exception e) {
e.printStackTrace();
I get the following stack trace in the readObject() call:
java.io.InvalidClassException:
weblogic.rmi.internal.LocalServerRefMissing no-arg constructor for
class
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1221)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
at java.io.ObjectInputStream.inputClassFields(ObjectInputStream.java:2263)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:519)
at weblogic.rmi.internal.StubInfo.readObject(StubInfo.java:73)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2214)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1411)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
at weblogic.ejb20.internal.HandleImpl.readExternal(HandleImpl.java:89)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1212)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
I suppose that WebLogic uses a different handle on the server
(LocalServerRef class, handle local to it's EJB) than on the client.
I took the routine from Apache SOAP 2.2 StatefulEJBProvider. So I
suppose that more people are running into the same problem.
Does anybody know of a workaround?
Tom

Answer 1

Just a small addition/clarification to what Cameron said on serialization.
- The no argument constructor is required in the first non-serializable class in the object hierarchy for de-serialization process. If your class extends form Object class(which has a no arg constructor), you need not have a no-arg constructor. refere to http://64.49.216.133/faq/view.jsp?EID=251942 for more details.
- Also I suggest using the api
isIdentical(...)
instead of equals method in the code if you are trying to establish whether the two objects represent the same EJBObject or not
- Rajeev
Cameron Purdy <[email protected]> wrote in message news:[email protected]...
A no-argument constructor is required for a class to be deserialized. It
sounds like a BEA bug from the stack trace, but make sure you don't have
something extra that you are serializing on something of yours that should
be transient. (It's hard to imagine how, but you never know ...)
Peace,
Cameron Purdy
Tangosol, Inc.
Clustering Weblogic? You're either using Coherence, or you should be!
Download a Tangosol Coherence eval today at http://www.tangosol.com/
"Tom Gerber" <[email protected]> wrote in message
news:[email protected]...
I try to serialize and later deserialize the handle of a stateful
session bean in WebLogic 6.1 SP2. This works on the client, but not on
the server. In WebLogic 6.1 SP1, it worked on both server and client.
The test code:
try {
InitialContext context = new InitialContext();
InfSessionHome sessionHome = (InfSessionHome)
InfEJBUtil.getInfEJBHome
(context, InfJNDINames.INFSESSION_EJBHOME,
InfSessionHome.class);
infSession1 = sessionHome.create();
// serialize
ObjectOutputStream objector = new ObjectOutputStream(byteStream);
objector.writeObject(infSession1.getHandle());
objector.flush();
objector.close();
byte[] ejbKeyBytes = byteStream.toByteArray();
// deserialize
ByteArrayInputStream byteInStream = new
ByteArrayInputStream(ejbKeyBytes);
ObjectInputStream objStream = new ObjectInputStream(byteInStream);
Handle ejbHandle = (Handle) objStream.readObject();
objStream.close();
InfSession infSession2 = (InfSession) ejbHandle.getEJBObject();
if (!infSession2.equals(infSession1)) {
throw new IllegalStateException("not equal: " + infSession2);
} catch (Exception e) {
e.printStackTrace();
I get the following stack trace in the readObject() call:
java.io.InvalidClassException:
weblogic.rmi.internal.LocalServerRefMissing no-arg constructor for
class
atjava.io.ObjectInputStream.inputObject(ObjectInputStream.java:1221)
atjava.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
atjava.io.ObjectInputStream.inputClassFields(ObjectInputStream.java:2263)
atjava.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:519)
at weblogic.rmi.internal.StubInfo.readObject(StubInfo.java:73)
at java.lang.reflect.Method.invoke(Native Method)
atjava.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2214)
atjava.io.ObjectInputStream.inputObject(ObjectInputStream.java:1411)
atjava.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
atjava.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
atweblogic.ejb20.internal.HandleImpl.readExternal(HandleImpl.java:89)
atjava.io.ObjectInputStream.inputObject(ObjectInputStream.java:1212)
atjava.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
atjava.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
I suppose that WebLogic uses a different handle on the server
(LocalServerRef class, handle local to it's EJB) than on the client.
I took the routine from Apache SOAP 2.2 StatefulEJBProvider. So I
suppose that more people are running into the same problem.
Does anybody know of a workaround?
Tom
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