"manik.surtani(a)jboss.com" wrote : Scott is right, this does apply to JBC as well. Currently what I do is I have a concept of cache regions, and users register class loaders per region. Any calls that are then sent over the wire contain the following: | | [version id: short][region id: serialized Fqn][payload] | | my unmarshalling code currently: | | 1. reads the version id and delegates to the appropriate unmarshaller | 2. unmarshaller reads the region id and sets the TCL appropriate to that region | 3. continues unmarshalling payload, etc | I would continue to do it exactly this way personally. The stream header mechanism should not be used to solve this problem (as designed today) - its purpose is just for verifying e.g. the stream's magic number (if there is one) and version number (if any). Assuming your region ID is a string, you can just use DataInput.readUTF to read it in (and DataOutput.writeUTF to write it out); should be fairly straightforward. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4169301#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...