My panel doesnt comes visible .....why?

Question

ive read, and ive been told that the only thing i need to make a panel and its contents visible is to make the panel visible by using the setVisible() method,
but iv tried that and it doesnt work, i dont know if i have to make visible each component in the panel or what, could anyone help me please??
Here is my code:
import java.io.*;
import java.util.Vector;
public class MainWin extends javax.swing.JFrame {
public static ClientesDB Clientes;
public static ProductosDB Productos;
public MainWin() {
initComponents();
private void jMenuItem1MouseClicked(java.awt.event.MouseEvent evt) {                                       
ClientPanel.setVisible(true);
private void jButton2MouseClicked(java.awt.event.MouseEvent evt) {                                     
Vector result;
if(buttonGroup1.getSelection().equals(jRadioButton1))
result=Clientes.Match_name(jTextField1.getText());
else{
if(buttonGroup1.getSelection().equals(jRadioButton2))
result=Clientes.Match_rfc(jTextField1.getText());
else{
if(buttonGroup1.getSelection().equals(jRadioButton3))
result=Clientes.Match_tel(jTextField1.getText());
else
result=new Vector(0);
if(result.size()==0)
jTextField1.setText("No hubo coincidencias o No selecciono un criterio de busqueda");
else
for(int i=0;i<result.size();i++)
jComboBox1.addItem(result.elementAt(i));
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {                                     
System.exit(0);
public static void main(String args[])throws IOException, ClassNotFoundException {
File path=new File("c://MaximaPresion//Database");
if(!path.exists())
path.mkdirs();
File clFile=new File(path, "clientes.txt");
if(!clFile.exists()){
clFile.createNewFile();
Clientes= new ClientesDB(500);
FileOutputStream FOS1=new FileOutputStream(clFile);
ObjectOutputStream out1=new ObjectOutputStream(FOS1);
out1.writeObject(Clientes);
out1.close();
FOS1.close();
out1=null;
FOS1=null;
} else{
FileInputStream FIS1=new FileInputStream(clFile);
ObjectInputStream in1=new ObjectInputStream(FIS1);
Clientes=(ClientesDB)in1.readObject();
in1.close();
FIS1.close();
in1=null;
FIS1=null;
File prFile=new File(path, "ptoductos.txt");
if(!prFile.exists()){
prFile.createNewFile();
Productos=new ProductosDB(500);
FileOutputStream FOS2=new FileOutputStream(prFile);
ObjectOutputStream out2=new ObjectOutputStream(FOS2);
out2.writeObject(Productos);
out2.close();
FOS2.close();
out2=null;
FOS2=null;
} else{
FileInputStream FIS2=new FileInputStream(prFile);
ObjectInputStream in2=new ObjectInputStream(FIS2);
Productos=(ProductosDB)in2.readObject();
in2.close();
FIS2.close();
in2=null;
FIS2=null;
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new MainWin().setVisible(true);
I skiped the variable declaration and the init components cause i dont think its necesary. could anyone help me?

Answer 1

it doesnt do anything so............ i think that must be it, ok........ im using netbeans, where do i find how to add the actionlistener to a menuItem?
I guess its not the same to add actions to a menuItem than to add em to a jButton, but i havent found how to do it, so could anyone tell me where to find it?