Given the documentation says that this is supposedly to be between JVMs, how do they handle the serialize/deserialize?
They punt on the actual serialization format: https://www.coralblocks.com/index.php/inter-process-communic...
In most applications like this you'll see direct byte manipulation to byte buffers because you want to pull as much performance as possible.
There are fast serialization formats like SBE that people leverage for this as well.