Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""

:? aew gente tá dando esse erro no meu código
Exception in thread “AWT-EventQueue-0” java.lang.NumberFormatException: For input string: “”
se puderem me ajudar eu agradeço muito !!!
:slight_smile:
ObS.: Código gerado pelo NB !!! só fiz alterar algumas coisas !

[code]
import javax.swing.*;
public class GUIdaLoja extends javax.swing.JFrame {

public GUIdaLoja() {
    initComponents();
    Carro[] c =new Carro[4];
    Importado[] im = new Importado[2];
    Nacional[] na= new Nacional[2];
 for ( int i=0 ; i<4 ; i++)
 {
 c[i] = new Carro();
 c[i].setMarca(m.getText());
 c[i].setAno(Integer.parseInt(a.getText()));
 c[i].setValor(Double.parseDouble(v.getText()));
}
}
                         
private void initComponents() {
    jLabel1 = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();
    jLabel3 = new javax.swing.JLabel();
    m = new javax.swing.JTextField();
    a = new javax.swing.JTextField();
    Combo = new javax.swing.JComboBox();
    BtCalc = new javax.swing.JButton();
    v = new javax.swing.JTextField();
    jComboBox1 = new javax.swing.JComboBox();
    jScrollPane1 = new javax.swing.JScrollPane();
    saida = new javax.swing.JTextArea();
    jPanel1 = new javax.swing.JPanel();
    Limpa = new javax.swing.JButton();
    btMostra = new javax.swing.JButton();
    jButton3 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    jLabel1.setText("Marca :");

    jLabel2.setText("Ano :");

    jLabel3.setText("Valor :");

    Combo.setFont(new java.awt.Font("Arial", 1, 11));
    Combo.setMaximumRowCount(2);
    Combo.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Nacional", "Importado" }));

    BtCalc.setText("Calcular");
    BtCalc.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            BtCalcActionPerformed(evt);
        }
    });

    jComboBox1.setMaximumRowCount(2);
    jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "R$", "U$" }));

    saida.setColumns(20);
    saida.setRows(5);
    jScrollPane1.setViewportView(saida);

    jPanel1.setBackground(new java.awt.Color(153, 204, 255));
    jPanel1.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED));
    Limpa.setMnemonic('L');
    Limpa.setText("LIMPAR");
    Limpa.setToolTipText("Limpa o campo de texto todo !!!");
    Limpa.setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);
    Limpa.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            LimpaActionPerformed(evt);
        }
    });

    btMostra.setMnemonic('O');
    btMostra.setText("OK");
    btMostra.setToolTipText("Mostra as Vari\u00e1veis digitadas !!!");
    btMostra.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            btMostraActionPerformed(evt);
        }
    });

    jButton3.setText("SAIR");

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                .addComponent(jButton3, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(btMostra, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(Limpa, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 91, Short.MAX_VALUE))
            .addContainerGap(46, Short.MAX_VALUE))
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(48, 48, 48)
            .addComponent(Limpa, javax.swing.GroupLayout.PREFERRED_SIZE, 33, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(15, 15, 15)
            .addComponent(btMostra, javax.swing.GroupLayout.PREFERRED_SIZE, 33, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(15, 15, 15)
            .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 38, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(156, Short.MAX_VALUE))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                        .addGroup(layout.createSequentialGroup()
                            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                .addComponent(jLabel1)
                                .addComponent(jLabel2)
                                .addComponent(jLabel3))
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                .addComponent(Combo, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addComponent(a)
                                .addComponent(m, javax.swing.GroupLayout.DEFAULT_SIZE, 137, Short.MAX_VALUE)))
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                            .addComponent(v)))
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                    .addComponent(BtCalc)))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 30, Short.MAX_VALUE)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(62, 62, 62)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel1)
                .addComponent(m, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(17, 17, 17)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel2)
                .addComponent(a, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(19, 19, 19)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel3)
                .addComponent(Combo, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(BtCalc))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(v, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(39, Short.MAX_VALUE))
        .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    pack();
}                       

private void btMostraActionPerformed(java.awt.event.ActionEvent evt) {                                         
    Carro[] c =new Carro[4];
    Importado[] im = new Importado[2];
    Nacional[] na = new Nacional[2];
    saida.setText(c.toString());
    saida.setText(na.toString());
    saida.setText(im.toString());
    
}                                        

private void LimpaActionPerformed(java.awt.event.ActionEvent evt) {                                      
m.setText(" ");
a.setText(" ");
v.setText(" ");
}                                     

private void BtCalcActionPerformed(java.awt.event.ActionEvent evt) {                                       
Carro[] c =new Carro[4];
Nacional[] na = new Nacional[2];
Importado[] im = new Importado[2];
    
if( Combo.getSelectedItem() == "Nacional")
{
    for (int w=0; w<2; w++)
    {  
    na[w]= new Nacional();
    na[w].setAumentaValor();
    }
}
else{
               
     for(int j =0; j <2; j++)
        {
            
            im[j] = new Importado();
            im[j].setAumentaValor();
        }
}
}                                      


public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new GUIdaLoja().setVisible(true);
        }
    });
}

                    
private javax.swing.JButton BtCalc;
private javax.swing.JComboBox Combo;
private javax.swing.JButton Limpa;
private javax.swing.JTextField a;
private javax.swing.JButton btMostra;
private javax.swing.JButton jButton3;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextField m;
private javax.swing.JTextArea saida;
private javax.swing.JTextField v;

}[/code]

Integer.parseInt ("") ou Double.parseDouble ("") não retorna 0, e sim ocasiona uma NumberFormatException. Antes de sair puxando os dados sem ver se eles estão preenchidos ou não, verifique se eles estão preenchidos e só então chame Integer.parseInt ou Double.parseDouble.

então como ficaria ?

desculpa… é q eu sou iniciante mesmo ! ^^