How do I get the maximum number of concurrent connections?

This example show you how to get the maximum number of concurrent connections to a database that are possible. To get this information we use the DatabaseMetaData.getMaxConnections() method call. If return value is zero it means that there is no limit or the limit is unknown.

package org.kodejava.example.sql;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.sql.DriverManager;

public class MaxConnections {
    public static void main(String[] args) {
        Connection connection = null;
        try {
            connection = getConnection();

            //
            // Get database meta data.
            //
            DatabaseMetaData metaData = connection.getMetaData();

            //
            // Retrieves the maximum number of concurrent
            // connections to this database that are possible.
            // A result of zero means that there is no limit or
            // the limit is not known.
            //
            int max = metaData.getMaxConnections();
            System.out.println("Max concurrent connections allowed: " + max);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                closeConnection(connection);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * Get a connection to database.
     * @return a connection to database.
     * @throws Exception when an exception occurs.
     */
    private static Connection getConnection() throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost/kodejavadb";
        return DriverManager.getConnection(url, "root", "");
    }

    /**
     * Close a connection to database.
     * @param connection a connection to be closed.
     * @throws SQLException when an exception occurs.
     */
    private static void closeConnection(Connection connection)
            throws SQLException {
        if (connection != null && !connection.isClosed()) {
            connection.close();
        }
    }
}

How do I check whether a driver is JDBC compliant?

package org.kodejava.example.sql;

import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;

public class JdbcCompliant {
    public static void main(String[] args) {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost/kodejavadb";
            Driver driver = DriverManager.getDriver(url);

            //
            // Check if the driver is a genuine JDBC compliant driver.
            //
            if (driver.jdbcCompliant()) {
                System.out.println("A genuine JDBC compliant driver");
            } else {
                System.out.println("Not a genuine JDBC compliant driver");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}