public class Driver implements java.sql.Driver

{

    // make these public so they can be used in setLogLevel below

    public static final int DEBUG = 2;

    public static final int INFO = 1;

    public static final int OFF = 0;

    private static final Logger logger = new Logger();

    private static boolean logLevelSet = false;

    private static Timer cancelTimer=null;

    static

    {

        try

        {

            // moved the registerDriver from the constructor to here

            // because some clients call the driver themselves (I know, as

            // my early jdbc work did - and that was based on other examples).

            // Placing it here, means that the driver is registered once only.

            java.sql.DriverManager.registerDriver(new Driver());

        }

        catch (SQLException e)

        {

            e.printStackTrace();

        }

    }

public static synchronized void registerDriver(java.sql.Driver driver)

        throws SQLException {

        registerDriver(driver, null);

    }

public static synchronized void registerDriver(java.sql.Driver driver,

            DriverAction da)

        throws SQLException {

        /* Register the driver if it has not already been added to our list */

        if(driver != null) {

            registeredDrivers.addIfAbsent(new DriverInfo(driver, da));

        } else {

            // This is for compatibility with the original DriverManager

            throw new NullPointerException();

        }

        println("registerDriver: " + driver);

    }

    private static Connection getConnection(

        String url, java.util.Properties info, Class<?> caller) throws SQLException {

        /*

         * When callerCl is null, we should check the application's

         * (which is invoking this class indirectly)

         * classloader, so that the JDBC driver class outside rt.jar

         * can be loaded from here.

         */

        ClassLoader callerCL = caller != null ? caller.getClassLoader() : null;

        synchronized(DriverManager.class) {

            // synchronize loading of the correct classloader.

            if (callerCL == null) {

                callerCL = Thread.currentThread().getContextClassLoader();

            }

        }

        if(url == null) {

            throw new SQLException("The url cannot be null", "08001");

        }

        println("DriverManager.getConnection(\"" + url + "\")");

        // Walk through the loaded registeredDrivers attempting to make a connection.

        // Remember the first exception that gets raised so we can reraise it.

        SQLException reason = null;

        for(DriverInfo aDriver : registeredDrivers) {

            // If the caller does not have permission to load the driver then

            // skip it.

            if(isDriverAllowed(aDriver.driver, callerCL)) {

                try {

                    println("    trying " + aDriver.driver.getClass().getName());

                    Connection con = aDriver.driver.connect(url, info);

                    if (con != null) {

                        // Success!

                        println("getConnection returning " + aDriver.driver.getClass().getName());

                        return (con);

                    }

                } catch (SQLException ex) {

                    if (reason == null) {

                        reason = ex;

                    }

                }

            } else {

                println("    skipping: " + aDriver.getClass().getName());

            }

        }

        // if we got here nobody could connect.

        if (reason != null)    {

            println("getConnection failed: " + reason);

            throw reason;

        }

        println("getConnection: no suitable driver found for "+ url);

        throw new SQLException("No suitable driver found for "+ url, "08001");

    }

}

/**

     * Load the initial JDBC drivers by checking the System property

     * jdbc.properties and then use the {@code ServiceLoader} mechanism

     */

    static {

        loadInitialDrivers();

        println("JDBC DriverManager initialized");

    }

private static void loadInitialDrivers() {

        String drivers;

        try {

            drivers = AccessController.doPrivileged(new PrivilegedAction<String>() {

                public String run() {

                    return System.getProperty("jdbc.drivers");

                }

            });

        } catch (Exception ex) {

            drivers = null;

        }

        // If the driver is packaged as a Service Provider, load it.

        // Get all the drivers through the classloader

        // exposed as a java.sql.Driver.class service.

        // ServiceLoader.load() replaces the sun.misc.Providers()

        AccessController.doPrivileged(new PrivilegedAction<Void>() {

            public Void run() {

                ServiceLoader<Driver> loadedDrivers = ServiceLoader.load(Driver.class);

                Iterator<Driver> driversIterator = loadedDrivers.iterator();

                /* Load these drivers, so that they can be instantiated.

                 * It may be the case that the driver class may not be there

                 * i.e. there may be a packaged driver with the service class

                 * as implementation of java.sql.Driver but the actual class

                 * may be missing. In that case a java.util.ServiceConfigurationError

                 * will be thrown at runtime by the VM trying to locate

                 * and load the service.

                 *

                 * Adding a try catch block to catch those runtime errors

                 * if driver not available in classpath but it's

                 * packaged as service and that service is there in classpath.

                 */

                try{

                    while(driversIterator.hasNext()) {

                        driversIterator.next();

                    }

                } catch(Throwable t) {

                // Do nothing

                }

                return null;

            }

        });

        println("DriverManager.initialize: jdbc.drivers = " + drivers);

        if (drivers == null || drivers.equals("")) {

            return;

        }

        String[] driversList = drivers.split(":");

        println("number of Drivers:" + driversList.length);

        for (String aDriver : driversList) {

            try {

                println("DriverManager.Initialize: loading " + aDriver);

                Class.forName(aDriver, true,

                        ClassLoader.getSystemClassLoader());

            } catch (Exception ex) {

                println("DriverManager.Initialize: load failed: " + ex);

            }

        }

    }