JDBC transaction commit case

import com.mysql.jdbc.Driver;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class JDBCDemo {
    public static void main(String[] args) throws Exception {

        //1  Get the connection 
        String url = "jdbc:mysql://IP:Port/db_name";
        String username = "username ";
        String password = "password ";
        Connection conn = DriverManager.getConnection(url, username, password);

        //2 sql  sentence 
        String sql = "update account set age=18 where id=1";
        //3  Access to perform sql The object of 
        Statement stmt = conn.createStatement();

        try {
            // Open transaction 
            conn.setAutoCommit(false);
            //4  perform sql
            int count = stmt.executeUpdate(sql);
            //5  Print processing results 
            System.out.println(count);
            // Commit transaction 
            conn.commit();

        } catch (Exception e) {
            conn.rollback();
            e.printStackTrace();

        }
        //6  Release resources 
        stmt.close();
        conn.close();
    }
}