code: public Jid getArchiveAddress() {
          if (archiveAddress == null) {
              EntityFullJid localJid = connection().getUser();
              if (localJid == null) {
                  return null;
              }
              return localJid.asBareJid();
          }
          return archiveAddress;
      }
docs: The the XMPP address of this MAM archive. Note that this method may return {@code null} if this MamManager
  handles the local entity's archive and if the connection has never been authenticated at least once.
  
  @return the XMPP address of this MAM archive or {@code null}.
  @since 4.3.0