How to pass a connection code?
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;

import javax.sql.DataSource;

public class DisplayUsers {

    ResultSet resultSet = null;
    Statement statement = null;
    Scanner input = new Scanner(System.in);
    DataSource ds = null;



    public void showAll() {

        System.out.println("Search User: ");
        String user = input.nextLine();

        String query = "Select * from user";
        try {
            resultSet = statement.executeQuery(query);
            ResultSetMetaData metadata = resultSet.getMetaData();
            int columns = metadata.getColumnCount();
            while(resultSet.next()){
                for(int i = 1 ; i<=columns;i++){
                    System.out.printf("%-8st",resultSet.getObject(i));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.sql.*;

public class Jdbc {

        public void dbConn(){
            final String url = "jdbc:mysql://localhost:3306/payroll";
            Connection conn = null;
            try{
                 Class.forName("com.mysql.jdbc.Driver");
                 conn = DriverManager.getConnection(url,"root","123192");
            }catch(Exception e){
                e.printStackTrace();
            }
        }
}

InitialContext ctx = new InitialContext();
//Application Server will automatically bind new InitialContext() call to its
//own context (where your DataSource is located).
DataSource ds = ctx.lookup("jndi/mydb")