I am currently creating a java method(part of and XPages managed bean) to retrieve a list groups a user(not necessarly current user) is a member of.
Is there any easy method to retieve this information or am i going to have to loop through all the groups to check for the user and also check if those groups are sub groups of other groups?
Answered this in a blog post here: http://ntf.gbs.com/nathan/escape.nsf/d6plinks/NTFN-8TMHRP
Simple version is that what you're looking for is...
lotus.notes.addins.DominoServer server = new lotus.notes.addins.DominoServer("YourCanonicalServerName");
Collection nameList = server.getNamesList("TheUserNameYou'reLookingFor");
That should be all you need.