Including JCheckBox in JFrame as and when a client connects

I am trying to write a server application in java and creating a vector v1 to store all the sockets that hit the server. Next i made an arraylist where i stored all my Client sockets as objects and then created a JCheckBox array where I loop it to add checkbox to the JPanel controlpanel which was initiated in the class contructor but something seems to be going wrong and i can't see any checkbox.

import java.util.*;
import java.net.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
import java.awt.*;

class server extends JFrame implements ActionListener
{
JTextArea t1;
PrintWriter pw;
JButton b1,b2;
static Vector v1=new Vector();
static ArrayList checks=new ArrayList();
static JPanel controlpanel;
server()
{
setLayout(new FlowLayout());
t1=new JTextArea();
add(t1);
b1=new JButton("Send to All");
b2=new JButton("Send");
//b1.addActionListener(this);
//b2.addActionListener(this);
add(b2,BorderLayout.SOUTH);

add(b1,BorderLayout.NORTH);
b1.addActionListener(this);
b2.addActionListener(this);
controlpanel=new JPanel();
controlpanel.setVisible(true);
add(controlpanel);
}

public void actionPerformed(ActionEvent ae)
{


    String m=t1.getText();
if(ae.getSource()==b1)
{
    try
    {
        Iterator t2=v1.iterator();
        while(t2.hasNext())
        {
            Socket s=(Socket)t2.next();
            pw=new PrintWriter(s.getOutputStream(),true);
            pw.println(m);
            pw.flush();
            System.out.println("send"+m);
        }
    }catch(Exception e){}
}
if(ae.getSource()==b2)
{
    try
    {
    Iterator itr=checks.iterator();
    while(itr.hasNext())
    {
        Socket schecked=(Socket)itr.next();
        pw=new PrintWriter(schecked.getOutputStream(),true);
        pw.println(m);
        pw.flush();
        System.out.println("sent "+m);

    }
    }
    catch(Exception e){}
}
t1.setText("");
}

public static void main(String z[])
{

    try {
        new server().setVisible(true);
        ServerSocket s=new ServerSocket(2000);
        while(true)
        {
            System.out.println("waiting...");
            Socket c=s.accept();
//          System.out.print(c);
            v1.add(c);
            for(int i=0;i<v1.size();i++)
            {   
                checks.add(v1.get(i));
//              checks[i].setText()=v1[i];
            }
            JCheckBox checkbox[]=new JCheckBox[checks.size()];

            for(int i=0;i<checks.size();i++)
            {
            //  Object o=checks.get(i);
                checkbox[i]= new JCheckBox();
//              checkbox[i].setText()=checks.get(i).name;
                controlpanel.add(checkbox[i]);
                checkbox[i].setSelected(true);
            }
        }
    }
    catch(Exception e)
    {
    e.printStackTrace();
    }
}
}