code: public RosterEntry getEntry(BareJid jid) {
          if (jid == null) {
              return null;
          }
          return entries.get(jid);
      }
docs: Returns the roster entry associated with the given XMPP address or
  <tt>null</tt> if the user is not an entry in the roster.
  
  @param jid the XMPP address of the user (eg "jsmith@example.com"). The address could be
  in any valid format (e.g. "domain/resource", "user@domain" or "user@domain/resource").
  @return the roster entry or <tt>null</tt> if it does not exist.