if (!isConnect()) {
      conn = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + database, user, password);
    }
  }

    MySQL.update("UPDATE `CoinSystem` SET Coins='" + removecoins + "' WHERE Name='" + Name + "'");

 public static void update(String qry)
    throws SQLException
  {
    PreparedStatement ps = conn.prepareStatement(qry);
    ps.executeUpdate();
    ps.close();
  }