Policy files and examples

[Con Lu]

When running an RMI example
1) Do you have to specify a security policy file for
BOTH the client and server machines
2) If so, do you run the server and client by commands such as the following?
java -Djava.security.policy=c:\DirOnServer\wideopen.policy myRMIServer
java -Djava.security.policy=c:\DirOnClient\wideopen.policy myRMIClient
3) Do the commands above have to refer to policy files on their own machines or if they don't how do you refer to a policy file on another machine?
I am getting very confused, and any help would be much appreciated!
By the way, I am having problems getting examples on the Internet (such as Sun's)to work. Many examples seem to brush over compilation and setup (or where to put certain files etc)- especially those examples concerning web-servers, dynamic class loading, and security files. Does anybody have links to good step-by-step examples / resources?
Thanks