It is a java program code to connect to MariaDB database in Ubuntu Operating system using the Connector/J JDBC

ConnectionDemo.java

import java.sql.*;

public class ConnectionDemo {

    public static void main(String[] arg){

        //Declaring the variables
        Connection con = null;
        Statement stm = null;
        ResultSet rs = null;

        try{
                //Connecting to the mariadb databse
                //database:test, user:root, password:root
                con = DriverManager.getConnection(
                "jdbc:mariadb://localhost:3306/test?user=root&password=root"
                );

                //Creating the sql query statements to select all the records from the user table
                stm = con.createStatement();
                rs = stm.executeQuery("SELECT * FROM user");

                //Accessing the record from one-by-one and printing it
                if(rs != null){
                    int i=1;
                    while(rs.next()){
                        System.out.println(
                            "\t\tRecord "+i+
                            "\nName:"+rs.getString("name")+
                            "\nAge:"+rs.getString("age") +
                            "\nGender:"+rs.getString("gender")
                            );
                        i++;
                    }
                
                //In case if the user table is empty
                }else{
                    System.out.println("User Table is Empty");
                }


                //Throwing the catch statement in case the connection is not established
        }catch(SQLException sqlEx){sqlEx.printStackTrace();}

        finally{

            //Releasing the ResultSet once it is no more required and assign it null value
            if(rs != null){
                try{
                    rs.close();
                }catch(SQLException sqlEx){sqlEx.printStackTrace();}
                rs = null;
            }

            //Releasing the createStatement once it is no more required and assign it null value
            if(stm != null){
                try{
                    stm.close();
                }catch(SQLException sqlEx){sqlEx.printStackTrace();}
                stm = null;
            }

            //Finally closing the database connection
            try{

                con.close();  
            }catch(Exception e){e.printStackTrace();}
            

        }

    }

}