The property java.rmi.server.codebase
is used to specify a URL. This URL points to a
file:, ftp:, or http: location which supplies classes for objects that are sent from this
JRE. If a program running in a JRE sends an object to another JRE (as the return value
from a method), that other JRE needs to load the class file for that object.
sends the object via serialization RMI embeds the URL specified by this parameter into
the stream, alongside of the actual object.
It is important to note that RMI does not send class files along with the serialized objects.
If the remote JRE needs to load a class file for an object, it looks for the embedded URL
and contacts the server at that location for the file.