How to JDBC with MariaDB example

/*Notes for others before you try this  You must grant all permission to root as follows otherwise this will not work
At command prompt to enter MySQL  type the following  mysql -u root -p
This will  request password from you  and if successful you should see the following
as prompt

MariaDB [(none)]>

At this prompt type the following below
GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY 'your password here';  ## now hit enter key

You should  have returned  this below or similar
Query OK, 1 rows affected (0.03 sec)

Now at the same prompt type like so  then hit the enter key
MariaDB [(none)]> quit

MD Harrington  23:42Hrs Saturday 8th February 2020

*/
package mariadb;


import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

public class SimpleJDBCApplication {
    // JDBC driver name and database URL

    static final String JDBC_DRIVER = "org.mariadb.jdbc.Driver";
    static final String DB_URL = "jdbc:mariadb://localhost/Business";

    //  Database credentials
   final String USER = "root";
   final String PASS = "xxxxx"; // Dont forget to put your password in here

    private Statement stmt = null ;
    private ResultSet rs ;

    private Properties props ;

    public SimpleJDBCApplication() {

        props = new Properties();
        props.put(this.USER,USER);
        props.put(this.PASS,PASS) ;
      }

    public Connection getConnection()
    {
        Connection conn = null ;


         System.out.println("Connecting to a selected database...");
        try {
            conn = DriverManager.getConnection(
                    DB_URL, props.getProperty(USER), props.getProperty(PASS));
        } catch (SQLException ex) {
            Logger.getLogger(SimpleJDBCApplication.class.getName()).log(Level.SEVERE, null, ex);
        }
            System.out.println("Connected database successfully...");

        return conn ;
    }


    public void executesql(Connection con , String sqlcommand){

        try {

            stmt = con.createStatement();

            stmt.executeUpdate(sqlcommand);

            System.out.println("Sql Success in given database...");


                    } catch (SQLException ex) {
            Logger.getLogger(SimpleJDBCApplication.class.getName()).log(Level.SEVERE, null, ex);
        } finally {
            //finally block used to close resources
            try {
                if (stmt != null) {
                    stmt.close();
                }
            } catch (SQLException se) {
            }// do nothing
            try {
                if (con != null) {
                    con.close();
                }
            } catch (SQLException se) {
                // deal with sql exceptions here

            }//end finally try
        }//end try


    }


    public void retrieveData(Connection con , String sql)
    {

        try {
            stmt = con.createStatement();
            rs = stmt.executeQuery(sql);


            // how to get the Max column count in your table

            ResultSetMetaData rsmd = rs.getMetaData();

            // this returns number of coloumbs in your table you created
            int numCols = rsmd.getColumnCount();

            /*Print the data to the console rs RS  or your record set contains the number of columns for matching
            records  */


            while(rs.next()){

                /*  Iterate through each column */
                /* Since I know that my table uses only VARCHAR type I need only use rs,GetString() method */

                for(int i= 1 ; i <=numCols ; i++ )
                {
                System.out.print("|" rs.getString(i) + "|" "\t" );
                }
                System.out.println(""); // add  a line  after printing this in tabbed format
            }
        } catch (SQLException ex) {
            Logger.getLogger(SimpleJDBCApplication.class.getName()).log(Level.SEVERE, null, ex);
        }finally {
            //finally block used to close resources
            try {
                if (stmt != null) {
                    stmt.close();
                }
            } catch (SQLException se) {
            }// do nothing
            try {
                if (con != null) {
                    con.close(); // always close the connection
                }
            } catch (SQLException se) {
                // deal with sql exceptions here

            }
        } //end finally try

    }


    public static void main(String[] args) {

        SimpleJDBCApplication myApp ; //  set aside your memory location for this object
        String sql ;  // for holding your sql commands

        myApp = new SimpleJDBCApplication() ; // create a new instance

       // create table

              sql = "CREATE TABLE IF NOT EXISTS CONTACTS" +
                   "(" +
                   " ClientId VARCHAR(30) not NULL, " +
                   " First_name VARCHAR(30), " +
                   " Last_Name VARCHAR(30), " +
                   " Telephone VARCHAR(30), " +
                   " Mobile VARCHAR(30), " +
                   " Email VARCHAR(40), " +
                   " PostCode VARCHAR(50), " +
                   " PRIMARY KEY (ClientId)" +
                   ")";

          myApp.executesql(myApp.getConnection(), sql); // invoke the method calls on your my App object

         // this will only run once  due to  using unique key    You cannot have tow or more records with same ID

              sql = "INSERT INTO Business.CONTACTS " +
                    "(ClientId, First_name, Last_Name, Telephone, Mobile, Email, PostCode) "+
                "VALUES ('HAR1234', 'Mark', 'Harrington', '0208 8218564', '07234 123123', 'someone@hotmail.com', 'BR3 3PZ')" ;


          myApp.executesql(myApp.getConnection(), sql);

 // check to see if your table was populated with above data

              sql = "SELECT * From  Business.CONTACTS " ;

          myApp.retrieveData(myApp.getConnection(), sql);

        System.out.println("Goodbye! \n From Main Method  \n Now you can start  creating a GUI to do this for you");
    }//end main
}//end JDBCExample