EN LA CLASE public class form extends javax.swing.JFrame { DefaultListModel obj1 = new DefaultListModel(); DefaultListModel obj2 = new DefaultListModel(); DefaultListModel obj3 = new DefaultListModel(); DefaultListModel obj4 = new DefaultListModel(); DefaultListModel obj5 = new DefaultListModel(); int numero=0;EN EL FORMULARIOpublic form() { initComponents(); estado(false); cmbprod.addItem("Layconsa"); cmbprod.addItem("Justus"); cmbprod.addItem("Standford"); cmbprod.addItem("College"); cmbprod.addItem("Alpha"); }

BTNCOMPRARprivate void btnComprarActionPerformed(java.awt.event.ActionEvent evt) { double precio=0; int cantidad = Integer.parseInt(String.valueOf(txtcant.getText())); String prod = String.valueOf(cmbprod.getSelectedItem()); switch (cmbprod.getSelectedIndex()) { case 0: precio=3.00; break; case 1: precio=2.50; break; case 2: precio=5.00; break; case 3: precio=4.50; break; case 4: precio=3.50; break; } double subtotal1=cantidad*precio; numero+=1; obj1.addElement(numero); obj2.addElement(prod); obj3.addElement(precio); obj4.addElement(cantidad); obj5.addElement(subtotal1); List1.setModel(obj1); List2.setModel(obj2);

List3.setModel(obj3); List4.setModel(obj4); List5.setModel(obj5); double subtotal=0; for(int x=0; x < List5.getModel().getSize();x++) {

subtotal = subtotal + (double) (Double.parseDouble(String.valueOf(List5.getModel().getElementAt(x)))); } txtsubtotal.setText(String.valueOf(subtotal)); txtdesct.setText(String.valueOf((double) (Double.parseDouble(String.valueOf(txtsubtotal.getText()))) * 0.10)); txtneto.setText(String.valueOf((double)(Double.parseDouble(String.valueOf(txtsubtotal.getText()))) - (double)(Double.parseDouble(String.valueOf(txtdesct.getText()))))); } BTNSALIR

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { this.dispose(); }HABILITARvoid estado(boolean v) { btnComprar.enable(v); cmbprod.enable(v); txtcant.enable(v); }BTNNUEVOprivate void jButton2ActionPerformed(java.awt.event.ActionEvent evt) { estado(true); txtcant.setText(""); txtsubtotal.setText(""); txtdesct.setText(""); txtneto.setText(""); numero=0; limpiar(); } LIMPIARpublic void limpiar(){ obj1.removeAllElements(); obj2.removeAllElements(); obj3.removeAllElements(); obj4.removeAllElements(); obj5.removeAllElements(); List1.setModel(obj1); List2.setModel(obj2); List3.setModel(obj3); List4.setModel(obj4); List5.setModel(obj5); }