public void update(String[] columnsArray, String[] valuesArray, String whereCol, String whereVal, String table){
       String sql = " UPDATE " + table + " SET ";
        for (int i = 0; i < columnsArray.length; i++) {
            sql += columnsArray[i] + " = '" + valuesArray[i] + "', ";
        }
        sql = sql.substring(0, sql.length() - 2);
        sql += " WHERE " + whereCol + " = '" + whereVal + "'";
        try{
            stmt = conn.createStatement();
            stmt.executeQuery(sql);
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
    }