src/main/java/org/jivesoftware/smack/RosterGroup.java
public RosterEntry getEntry(String user) {
        if (user == null) {
            return null;
        }
        // Roster entries never include a resource so remove the resource
        // if it's a part of the XMPP address.
        user = StringUtils.parseBareAddress(user);
        String userLowerCase = user.toLowerCase();
        synchronized (entries) {
            for (RosterEntry entry : entries) {
                if (entry.getUser().equals(userLowerCase)) {
                    return entry;
                }
            }
        }
        return null;
    }
public RosterEntry getEntry(String user) {
        if (user == null) {
            return null;
        }
        // Roster entries never include a resource so remove the resource
        // if it's a part of the XMPP address.
        user = StringUtils.parseBareAddress(user);
        String userLowerCase = user.toLowerCase();
        synchronized (entries) {
            for (RosterEntry entry : entries) {
                if (entry.getUser().equals(userLowerCase)) {
                    return entry;
                }
            }
        }
        return null;
    }
Returns the roster entry associated with the given XMPP address or
<tt>null</tt> if the user is not an entry in the group.

@param user
the XMPP address of the user (eg "jsmith@example.com").
@return the roster entry or <tt>null</tt> if it does not exist in the
group.