Java APIs

Hi! I am trying to deploy weblogic 9.2MP3 with java 6, because java 5 is so close to end of life. I have been able to resolve some issues, but this one just doesn't Google. That is, invalid type code: 90 never comes up with any hits. This is coming from a java.rmi.UnmarshalException error in unmarshalling arguments, and I understand it may have to do with class loading and array class name syntax (at least for invalid type code AC), but setting -Dsun.lang.ClassLoader.allowArraySyntax=true does not help in this case. It also looks like it may be involved in authentication. Can anyone tell me what an invalid type code: 90 is specifically and a way I might try to work around it! thanks!

Using 1.6.0_14

This Exception occured at Mon Aug 03 14:31:28 MDT 2009.
javax.naming.CommunicationException [Root exception is java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.io.StreamCorruptedException: invalid type code: 90]
at weblogic.jndi.internal.ExceptionTranslator.toNamingException(ExceptionTranslator.java:85)
at weblogic.jndi.internal.ExceptionTranslator.toNamingException(ExceptionTranslator.java:41)
at weblogic.jndi.WLInitialContextFactoryDelegate.toNamingException(WLInitialContextFactoryDelegate.java:773)
at weblogic.jndi.WLInitialContextFactoryDelegate.pushSubject(WLInitialContextFactoryDelegate.java:673)
at weblogic.jndi.WLInitialContextFactoryDelegate.newContext(WLInitialContextFactoryDelegate.java:466)
at weblogic.jndi.WLInitialContextFactoryDelegate.getInitialContext(WLInitialContextFactoryDelegate.java:373)
at weblogic.jndi.Environment.getContext(Environment.java:307)
at weblogic.jndi.Environment.getContext(Environment.java:277)
at weblogic.jndi.WLInitialContextFactory.getInitialContext(WLInitialContextFactory.java:117)
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:667)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
at javax.naming.InitialContext.init(InitialContext.java:223)
at javax.naming.InitialContext.<init>(InitialContext.java:197)
etc.....
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.io.StreamCorruptedException: invalid type code: 90
at weblogic.rjvm.ResponseImpl.unmarshalReturn(ResponseImpl.java:215)
at weblogic.rmi.internal.BasicRemoteRef.invoke(BasicRemoteRef.java:224)
at weblogic.common.internal.RMIBootServiceImpl_923_WLStub.authenticate(Unknown Source)
at weblogic.security.acl.internal.Security$1.run(Security.java:185)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:147)
etc....
Caused by: java.io.StreamCorruptedException: invalid type code: 90
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1356)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
at weblogic.utils.io.ChunkedObjectInputStream.readObject(ChunkedObjectInputStream.java:195)
at weblogic.rjvm.MsgAbbrevInputStream.readObject(MsgAbbrevInputStream.java:565)
at weblogic.utils.io.ChunkedObjectInputStream.readObject(ChunkedObjectInputStream.java:191)
at weblogic.common.internal.RMIBootServiceImpl_WLSkel.invoke(Unknown Source)
at weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:553)
at weblogic.rmi.internal.BasicServerRef$1.run(BasicServerRef.java:443)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)