JDBC - insert, delete, display, Connnection Database

Display connection mysql workbench
Install : https://www.youtube.com/watch?v=V8F-RxzI_2w
1- Insert /2-Delete/3-Display/ 4-Exit
3
Connecting to database...

ID: 1, Name: Dai, Class: cl, Age: 13
ID: 3, Name: Dang, Class: cl, Age: 20
ID: 4, Name: Tho, Class: cl, Age: 28
ID: 6, Name: Long, Class: cl, Age: 6
ID: 8, Name: Link, Class: po, Age: 22
ID: 9, Name: Lin, Class: cl, Age: 22
ID: 10, Name: Huynh, Class: po, Age: 24
ID: 11, Name: Phung, Class: po, Age: 24
ID: 12, Name: Yen, Class: po, Age: 24
ID: 13, Name: y, Class: po, Age: 22
ID: 14, Name: Long, Class: po, Age: 24

 Example: 

package aptech;

public class Test {
 public static void main(String[] args) {
  DataConsole dc = new DataConsole();
  dc.start();
 }
}

package aptech;

import java.util.Scanner;

public class DataConsole {

 public void start() {

  while (true) {
   int choice = menu();
   switch (choice) {
   case 1:
    insert();
    break;
   case 2:
    delete();
    break;
   case 3:
    display();
    break;
   case 4:
    System.out.println("GoodBye!");
    System.exit(0);

   }
  }
 }

 public int menu() {
  System.out.println("\n1- Insert /2-Delete/3-Display/ 4-Exit");
  int choice = readln();
  return choice;
 }

 Scanner s = new Scanner(System.in);

 public int readln() {
  int n = 0;
  try {
   n = Integer.parseInt(s.nextLine());
  } catch (Exception e) {
   // TODO: handle exception
  }
  return n;
 }

 DataManager control = new DataManager();
 
 public void insert() {
  control.insert();
 }

 public void delete() {
  control.delete();
 }

 public void display() {
  control.display();
 }
}

package aptech;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;

public class DataManager {
 // JDBC driver name and database URL
 static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
 static final String DB_URL = "jdbc:mysql://localhost/simple";
 // Database credentials
 static final String USER = "root";
 static final String PASS = "1234567";

 public void insert() {
  Connection conn = null;
  Statement stmt = null;
  try {
   // STEP 2: Register JDBC driver
   Class.forName("com.mysql.jdbc.Driver");

   // STEP 3: Open a connection
   System.out.println("Connecting to a selected database...");
   conn = DriverManager.getConnection(DB_URL, USER, PASS);
   System.out.println("Connected database successfully...");

   // STEP 4: Execute a query
   System.out.println("Inserting records into the table...");
   stmt = conn.createStatement();

   Scanner scanner = new Scanner(System.in);
   String yes = "";
   do {
    System.out.print("Name: ");
    String name = scanner.nextLine();
    System.out.print("Class: ");
    String clas = scanner.nextLine();
    System.out.print("Age: ");
    int age = Integer.parseInt(scanner.nextLine());
    String sql = "INSERT INTO `simple`.`person` (`Name`, `class`, `age`) VALUES ('" + name + "', '" + clas
      + "', '" + age + "')";
    System.out.println("Sql: " + sql);
    stmt.executeUpdate(sql);
    System.out.println("Inserted records into the table...");
    System.out.println("Exit [y/n]");
    yes = scanner.nextLine();

   } while (yes.compareTo("y") != 0);

  } catch (SQLException se) {
   // Handle errors for JDBC
   // se.printStackTrace();
  } catch (Exception e) {
   // Handle errors for Class.forName
   // e.printStackTrace();
  } finally {
   // finally block used to close resources
   try {
    if (stmt != null)
     conn.close();
   } catch (SQLException se) {
   } // do nothing
   try {
    if (conn != null)
     conn.close();
   } catch (SQLException se) {
    // se.printStackTrace();
   } // end finally try
  } // end try
 }

 public void delete() {
  Connection conn = null;
  Statement stmt = null;
  try {
   // STEP 2: Register JDBC driver
   Class.forName("com.mysql.jdbc.Driver");

   // STEP 3: Open a connection
   System.out.println("Connecting to a selected database...");
   conn = DriverManager.getConnection(DB_URL, USER, PASS);
   System.out.println("Connected database successfully...");

   // STEP 4: Execute a query
   System.out.println("Inserting records into the table...");
   stmt = conn.createStatement();

   Scanner scanner = new Scanner(System.in);
   String yes = "";
   do {
    System.out.print("Number ID: ");
    String id = scanner.nextLine();
    
    String sql = "DELETE FROM `simple`.`person` WHERE `ID`='"+id+"'";
    System.out.println("Sql: " + sql);
    stmt.executeUpdate(sql);
    System.out.println("DELETE records into the table...");
    System.out.println("Exit [y/n]");
    yes = scanner.nextLine();

   } while (yes.compareTo("y") != 0);

  } catch (SQLException se) {
   // Handle errors for JDBC
   // se.printStackTrace();
  } catch (Exception e) {
   // Handle errors for Class.forName
   // e.printStackTrace();
  } finally {
   // finally block used to close resources
   try {
    if (stmt != null)
     conn.close();
   } catch (SQLException se) {
   } // do nothing
   try {
    if (conn != null)
     conn.close();
   } catch (SQLException se) {
    // se.printStackTrace();
   } // end finally try
  } // end try
 }

 public void display() {
  // TODO Auto-generated method stub
  Connection conn = null;
  Statement stmt = null;
  try {
   // STEP 2: Register JDBC driver
   Class.forName("com.mysql.jdbc.Driver");
   // STEP 3: Open a connection
   System.out.println("Connecting to database...");
   conn = (Connection) DriverManager.getConnection(DB_URL, USER, PASS);
   // STEP 4: Execute a query
   System.out.println("Creating statement...");
   stmt = (Statement) conn.createStatement();

   String sql = "SELECT ID, Name, class, age FROM person WHERE age<30;";
   ResultSet rs = stmt.executeQuery(sql);
   // STEP 5: Extract data from result set
   while (rs.next()) {
    // Retrieve by column name
    int id = rs.getInt("ID");
    String name = rs.getString("Name");
    String clas = rs.getString("class");
    int age = rs.getInt("age");
    // Display values
    System.out.print("\nID: " + id);
    System.out.print(", Name: " + name);
    System.out.print(", Class: " + clas);
    System.out.print(", Age: " + age);
   }
   // STEP 6: Clean-up environment
   rs.close();
   stmt.close();
   conn.close();
  } catch (SQLException se) {
   // Handle errors for JDBC
   se.printStackTrace();
  } catch (Exception e) {
   // Handle errors for Class.forName
   e.printStackTrace();
  } finally {
   // finally block used to close resources
   try {
    if (stmt != null)
     stmt.close();
   } catch (SQLException se2) {
   } // nothing we can do
   try {
    if (conn != null)
     conn.close();
   } catch (SQLException se) {
    se.printStackTrace();
   } // end finally try
  } // end try
 }
}

Connection Database mysql Xampl + eclip

https://www.youtube.com/watch?v=4PeuMjDNYhI