Desconto

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Desconto extends JFrame implements ActionListener {
JLabel L1, L2, L3, L4;
JButton B1, B2;
JTextField T1, T2;
Desconto(){
setTitle("Calculo de Desconto");
setSize(320,320);
getContentPane().setBackground(Color.white);
getContentPane().setLayout(new GridLayout(4,2));
L1= new JLabel("Valor");
L2= new JLabel("% de Desconto");
L3= new JLabel("Valor com Desconto:");
L3.setFont(new Font ("Arial",Font.BOLD,14));
L4= new JLabel("");
Font.BOLD,14));
B1= new JButton("Calcular");
}
L4.setFont(new Font ("Arial",
B1.addActionListener(this);
B2= new JButton("Limpar");
B2.addActionListener(this);
T1= new JTextField(10);
T2= new JTextField(10);
getContentPane().add(L1);
getContentPane().add(T1);
getContentPane().add(L2);
getContentPane().add(T2);
getContentPane().add(B1);
getContentPane().add(B2);
getContentPane().add(L3);
getContentPane().add(L4);
public void actionPerformed(ActionEvent a){
if (a.getSource()==B1){
float valor=0, desconto=0;
try{
valor=Float.parseFloat(T1.getText());
desconto=Float.parseFloat(T2.getText())/100;
valor=valor*desconto;
L4.setText(""+valor);
}
catch (NumberFormatException erro){
JOptionPane.showMessageDialog(null,"Erro no formato dos
dados");
}
}
}
public static void main(String args[]){
JFrame Janela= new Desconto();
Janela.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Janela.setVisible(true);
}
}