usuario.java

import javax.swing.*;
import java.awt.event.*;

public class Formulario extends JFrame implements ActionListener{

 private JTextField textfield1;
 private JLabel label1;
 private JButton boton1;
 
 public Formulario(){
  setLayout(null);
  label1 = new JLabel("Usuario:");
  label1.setBounds(10,10,100,30);
  add(label1);

  textfield1 = new JTextField("");
  textfield1.setBounds(120,17,150,20);
  add(textfield1);

  boton1 = new JButton("Aceptar");
  boton1.setBounds(10,80,100,30);
  add(boton1);
  boton1.addActionListener(this);
 }
 
 public void actionPerformed(ActionEvent e){
  if(e.getSource() == boton1){
   String texto = textfield1.getText();
   setTitle(texto);
  }
 }
 public static void main(String args[]){
  Formulario formulario1 = new Formulario();
  formulario1.setBounds(0,0,300,150);
  formulario1.setVisible(true);
  formulario1.setResizable(false);
  formulario1.setLocationRelativeTo(null); 
 }
}