I am doing a grid service using Globus Toolkit3.0. now I have created a DirectoryFactoryService. how can I return an object to client from server. when i tried to return the object, an error is coming such as: "(0)null". Is this any problem relating RMI? if so how can i overcome it?
Another question is that,i have a portal and i want to know which systems are currently logged into that portal, and when each system is logging and logging out. can i get any code regarding this in java?