ReNcOoR

import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;



public class lap3 extends JFrame implements ActionListener{

        private JTextField t1, t2, t3, t4, t;
        private JLabel l1, l2, l3, l4, l;
        private JButton boton;
        private JTextArea area;
        private JScrollPane barra;



        public lap3 (){

            super("Example_Class");
            this.setSize(400, 600);
            centrarventana();
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            this.setResizable(false);
            this.setLayout(null);

            creargui();






        }

        private void creargui (){

            t  = new JTextField();
            t1 = new JTextField();
            t2 = new JTextField();
            t3 = new JTextField();
            t4 = new JTextField();

            l  = new JLabel("Cambiar Marca");
            l1 = new JLabel("Cambiar Modelo");
            l2 = new JLabel("Cambiar Tamaño Memoria");
            l3 = new JLabel("Cambiar Precio");
            l4 = new JLabel("Objetos Utilizados");

            area = new JTextArea();
            barra = new JScrollPane(area);
            boton = new JButton("Desplegar Lista");

            this.add(l);
            l.setBounds(10, 20, 100, 20);
            this.add(t);
            t.setBounds(10, 50, 200, 25);
            this.add(l1);
            l1.setBounds(10, 80, 100, 20);
            this.add(t1);
            t1.setBounds(10, 110, 200, 25);
            this.add(l2);
            l2.setBounds(10, 140, 150, 20);
            this.add(t2);
            t2.setBounds(10, 170, 200, 25);
            this.add(l3);
            l3.setBounds(10, 200, 100, 20);
            this.add(t3);
            t3.setBounds(10, 230, 200, 25);
            this.add(l4);
            l4.setBounds(155, 360, 150, 20);
            this.add(t4);
            t4.setBounds(185, 330, 40, 25);

            this.add(boton);
            boton.setBounds(130, 280, 150, 30);
            boton.addActionListener(this);

            this.add(barra);
            barra.setBounds(10, 390, 375, 150 );






        }

        private void centrarventana (){

            Dimension pantalla = Toolkit.getDefaultToolkit().getScreenSize();

            Dimension ventana = getSize();

            setLocation((pantalla.width - ventana.width) /2, (pantalla.height - ventana.height) /2);
        }



        public void actionPerformed(ActionEvent e) {


        }

    }