private MyConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(MyConnection.class.getName()).
                    log(Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            Logger.getLogger(MyConnection.class.getName()).
                    log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            Logger.getLogger(MyConnection.class.getName()).
                    log(Level.SEVERE, null, ex);
        }
        
        try {
            this.con = DriverManager.getConnection(
                    "jdbc:mysql://192.168.56.21:3306/Biblioteca",
                    "testing",
                    "021$"
            );
        } catch (SQLException ex) {
            Logger.getLogger(MyConnection.class.getName()).
                    log(Level.SEVERE, null, ex);
        }
    }