Calculadora em Java com Swing

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

public class AimeuCoracao extends JFrame implements ActionListener{

    JButton limpar = new JButton("Limpar");
    JButton calcular = new JButton("Calcular");
    JButton soma = new JButton("+");
    JButton subt = new JButton("-");
    JButton mult = new JButton("*");
    JButton divi = new JButton("/");

    JTextField login = new JTextField();
    JTextField senha = new JTextField();
    JTextField resul = new JTextField();



    public AimeuCoracao() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(500,400);
        setTitle("Ela que me diz..");                                           // PROPRIEDADES DA JANELA
        setResizable(false);
        getContentPane().setLayout(null);




       soma.setBounds(70, 195, 50, 20);
       getContentPane().add(soma);
       soma.addActionListener(this);

       subt.setBounds(130, 195, 50, 20);
       getContentPane().add(subt);
       subt.addActionListener(this);
                                                                                //OPERADORES
       mult.setBounds(190, 195, 50, 20);
       getContentPane().add(mult);
       mult.addActionListener(this);

       divi.setBounds(250, 195, 50, 20);
       getContentPane().add(divi);
       divi.addActionListener(this);





       login.setBounds(120, 145, 140, 20);
       getContentPane().add(login);

       senha.setBounds(120, 170, 140, 20);
       getContentPane().add(senha);                                             //CAIXAS DE TEXTO

       resul.setBounds(120, 220, 140, 20);
       getContentPane().add(resul);




       calcular.setBounds(135, 320, 100, 20);
       getContentPane().add(calcular);
       calcular.addActionListener(this);
                                                                                //BOTÕES
       limpar.setBounds(135, 350, 100, 20);
       getContentPane().add(limpar);
       limpar.addActionListener(this);

    }


    public static void main(String[] args) {

        AimeuCoracao janela = new AimeuCoracao();
        janela.setVisible(true);
        janela.show();

    }

    public void actionPerformed(ActionEvent acao) {

         double num1 = Double.parseDouble(login.getText());
         double num2 = Double.parseDouble(senha.getText());
         double result = num1 + num2;

         if(acao.getSource() == soma) {

                           calcular.setEnabled(true);
                   }
                     if(acao.getSource() == calcular) {
                            double num1 = Double.parseDouble(login.getText());
                            double num2 = Double.parseDouble(senha.getText());
                            double result = num1 + num2;
                              resul.setText(""+result);
                    }
        if(acao.getSource() == subt) {

                           calcular.setEnabled(true);
                   }
                     if(acao.getSource() == calcular) {
                             double num1 = Double.parseDouble(login.getText());
                            double num2 = Double.parseDouble(senha.getText());
                            double result = num1 - num2;
                              resul.setText(""+result);
                    }
         if(acao.getSource() == mult) {

                           calcular.setEnabled(true);
                   }
                     if(acao.getSource() == calcular) {
                              double num1 = Double.parseDouble(login.getText());
                            double num2 = Double.parseDouble(senha.getText());
                            double result = num1 * num2;
                              resul.setText(""+result);
                    }

         if(acao.getSource() == divi) {

                           calcular.setEnabled(true);
                   }
                     if(acao.getSource() == calcular) {
                            double num1 = Double.parseDouble(login.getText());
                            double num2 = Double.parseDouble(senha.getText());
                            double result = num1 / num2;
                              resul.setText(""+result);
                    }
        if(acao.getSource() == limpar) {

            login.setText("");
            senha.setText("");
            resul.setText("");
            login.requestFocus();
        }
    }

}