Thread: how to check is DOUBLE JTEXTFIELD is empty?

hi I've been working this for 2 days and even google it but I can't figured the right answer.
I can check STRING if it is empty.
here is my code

 
 private void saveButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                            
        String inventcodef = inventCodeField.getText();
        String inventnamef = inventNameField.getText();
        String categ = cmbname.getSelectedItem().toString();
        double inventreorderf = Double.parseDouble(inventReorderField.getText());
        String inventlocf = inventLocationField.getText();
        String inventstat = inventStatusArea.getText();
 
 
 
 
            if ((inventcodef.trim().length()==0) || (inventnamef.trim().length()== 0)||(inventreorderf == 0))
        {
 
         JOptionPane.showMessageDialog(null,"Item Code / Item Name / ReOrderpoint is empty!");  
 
 
        }
            else
 
        try {
            String SQL2 = "INSERT INTO inventory VALUES ("
                    + "'" + inventcodef + "'" + ","
                    + "'" + inventnamef + "'" + ","
                      + "'" + categ + "'" + ","
                    + "'" + inventreorderf + "'" + ","
                    + "'" + inventlocf + "'" + ","
                    + "'" + inventstat + "'"
                    + ")";
 
            PreparedStatement stamt = connect.prepareStatement(SQL2);
            stamt.executeUpdate();
            Double.parseDouble(inventReorderField.getText());
 
            JOptionPane.showMessageDialog(null,"Item Code: " + inventcodef + " Successfully saved!");
 
        }
          catch (NumberFormatException e)
          {
 
         JOptionPane.showMessageDialog(null,e.getMessage());
         inventReorderField.selectAll();
         inventReorderField.requestFocus();
         return;
 
          }
 
        catch (Exception f)
            {
             JOptionPane.showMessageDialog(null,(f.getMessage())); 
        }
 
 
 
    }

Thank you!