public static JID fromString(String jid) {
        Log.trace("Parsing JID from string: {}", jid);
        return fromJID(new JID(jid));
    }
Creates a JID from the given string. If the string represents a group,
return an instance of this class, otherwise returns a regular JID.

@param jid A JID, possibly representing a group
@return A JID with a type appropriate to its content
@throws IllegalArgumentException the given string is not a valid JID
xmppserver/src/main/java/org/jivesoftware/openfire/group/GroupJID.java