Please see the attached test case.

java.util.Calendar is not interoperable between JDK 1.3.1_xx and 1.4.0. The class has evolved and is trying to rely on reading more data than it might have, getting an exception, and still assuming that the stream position is valid.

This is possible in RMI-JRMP, but much more difficult in RMI-IIOP.

Conversations with Simon Nash suggest that it may be possible by
1) Detect hitting the valuetype end tag while data is being read
2) Detect an attempt by readObject() to read additional data from values that were marshaled as non-custom

but this doesn't appear to work with fragmentation. More analysis required.