Using Charles HTTP proxy, under Seam 2.2.1.CR1 a call to a simple server side method that returned a Boolean gave the following HEX output in the response:

00000000 72 01 00 46 7a r Fz


After upgrading to a recent snapshot of Seam 2.2.1, the output changed to:

00000000 72 02 00 48 00 0e 63 6f 6e 76 65 72 73 61 74 69 r H conversati
00000010 6f 6e 49 64 4e 46 7a onIdNFz

My JavaFX client could not handle this new format and reported a Hessian unexpected byte message.

I resolved the issue by editing HessianSeamContextualInvoker.process() to prevent the conversation ID from being added:

public void process() throws Exception {

invoke();

if (protocolVersion >= HESSIAN_PROTOCOL_MAJOR_VERSION) {
// out.writeHeader(FlamingoSeamConstants.HEADER_CONVERSATION_ID);
if (Manager.instance().isLongRunningConversation()) {
out.writeObject(Manager.instance().getCurrentConversationId());
} else {
// out.writeObject(null);
}
}
}