Classe ConnectionFactory

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ConnectionFactory {
    private static final String DRIVER = "com.mysql.jdbc.Driver";
    private static final String URL = "jdbc:mysql://localhost:3306/dbsistemacsl";
    private static final String USER = "root";
    private static final String PASS = "";

    public static Connection getConnection() {
        try {
            Class.forName(DRIVER);
            return DriverManager.getConnection(URL, USER, PASS);
        } catch (ClassNotFoundException | SQLException ex) {
            throw new RuntimeException("Erro na conexão: ", ex);
        }
    }

    public static void closeConnection(Connection con) {
        try {
            if (con != null) {
                con.close();
            }
        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(
                    Level.SEVERE, null, ex);
        }
    }

    public static void closeConnection(Connection con, PreparedStatement stmt) {
        closeConnection(con);
        try {
            if (stmt != null) {
                stmt.close();
            }
        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(
                    Level.SEVERE, null, ex);
        }
    }

    public static void closeConnection(Connection con, PreparedStatement stmt,
            ResultSet rs) {

        closeConnection(con, stmt);

        try {

            if (rs != null) {
                rs.close();
            }

        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}