ServerDatabase[] users = userList.getUsers();
DatabaseReference[] users = userList.getUsers(); ServerDatabase[] sd = new ServerDatabase[users.length]; for (int j = 0; j < users.length; j++) try { sd[j] = users[j].getServerDatabase(); } catch (IOException e) { e.printStackTrace(); }
  public ServerDatabase findOrphans() {    ServerDatabase orphans = new ServerDatabase();    Track[] tracks = getTracks();    ServerDatabase[] users = userList.getUsers();    for (int i = 0; i < tracks.length; i++) {      add: {        for (int j = 0; j < users.length; j++)           if (users[j].getTrack(tracks[i]) != null)            break add;        orphans.add(tracks[i]);      }    }    return orphans;  }