我编的聊天程序,为什么程序不能正常退出

程序运行没问题,但是退出时,控制台并没有释放资源,必须要ctrl+c;
Talk:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.*;
import java.io.*;public class Talk extends JFrame implements ActionListener,Runnable
{
 JButton button;
 JTextArea text1,text2;
 DatagramPacket sendData=null,receiveData=null;
 DatagramSocket sendSocket=null,receiveSocket=null;
 byte b1[],b2[];
 Thread receiveThread=null;
 JScrollPane jscrollpane1,jscrollpane2;
 JPanel panel1,panel2,panel3;
 Container con=null;
 JSplitPane jsplitpane,jsplitpane1;
 JLabel label;
 JTextField textfield; Talk()
 {//***界面的制作
  setVisible(true);
  setBounds(200,200,400,400);
  setDefaultCloseOperation(DISPOSE_ON_CLOSE);
  setResizable(false);
  button=new JButton("发送");
  button.addActionListener(this);
  text1=new JTextArea();
  text1.setEditable(false);
  text2=new JTextArea();
  text2.setText("");
  jscrollpane1=new JScrollPane(text1);
  jscrollpane2=new JScrollPane(text2);
  label=new JLabel("请输入IP地址:");
  textfield=new JTextField(20);
  textfield.setText("");
  panel1=new JPanel();
  panel1.setLayout(new BorderLayout());
  panel1.setVisible(true);
  panel1.setBounds(0,0,200,200);
  panel1.add(jscrollpane1,BorderLayout.CENTER);
  panel1.validate();
  panel2=new JPanel();
  panel2.setLayout(new BorderLayout());
  panel2.setVisible(true);
  panel2.setSize(100,100);
  panel2.add(jscrollpane2,BorderLayout.CENTER);
  panel2.validate();
  panel3=new JPanel();
  panel3.setVisible(true);
  panel3.setLayout(null);
  panel3.add(button);
  panel3.add(label);
  panel3.add(textfield);
  label.setBounds(10,0,80,30);
  textfield.setBounds(100,0,100,25);
  button.setBounds(310,0,60,30);
  jsplitpane=new JSplitPane(JSplitPane.VERTICAL_SPLIT,panel1,panel2);
  jsplitpane.setDividerLocation(250);
  jsplitpane1=new JSplitPane(JSplitPane.VERTICAL_SPLIT,jsplitpane,panel3);
  jsplitpane1.setDividerLocation(330);
  con=getContentPane();
  con.add(jsplitpane1,BorderLayout.CENTER);
  validate();
  //***界面
  receiveThread=new Thread(this);
  receiveThread.start();
  
 }//Talk()
 public void run()
 {
  try{
  b1=new byte[10];
  receiveData=new DatagramPacket(b1,b1.length);
  receiveSocket=new DatagramSocket(6819);
  }catch(IOException a){}
  while(true)
  {
   try{
   receiveSocket.receive(receiveData);
   }catch(IOException aa){continue;}
   String s=new String(b1).trim();
   text1.append("对方说:"+"\n");
   text1.append(new String(b1)+"\n");
  }//while()
 } 
 public void actionPerformed(ActionEvent e)
 {
  if(e.getSource()==button)
  {
   
   if(!textfield.getText().equals(""))
   {
    
    if(!text2.getText().equals(""))
    {
     try{
     String s=textfield.getText();
     String s1=text2.getText();
     b2=s1.getBytes();
     InetAddress address=InetAddress.getByName(s);
     sendData=new DatagramPacket(b2,b2.length,address,6819);
     sendSocket=new DatagramSocket();
     sendSocket.send(sendData); 
     text2.setText("");
     text1.append("我说:"+"\n");
     text1.append(s1+"\n");
     
    }catch(IOException aa){}
    }//if(text2.getText()!=null)
    else {JOptionPane.showMessageDialog(this,"不能发空消息","error",JOptionPane.INFORMATION_MESSAGE);}
   }//if(textfield.getText()!=null)
   else {JOptionPane.showMessageDialog(this,"IP地址未输入","error",JOptionPane.WARNING_MESSAGE);}
  }
 } public static void main(String args[])
 {new Talk();}
}//class Talk