AWT-EventQueue-5!!!

[Sonal Sharma]

Dear all,
I am having a program that is creating this stack trace.Please help me out.
Thanks

My program is as following:

import java.io.*;
import java.net.*;
import java.text.*;
import java.util.*;
import java.awt.*;
import java.applet.*;
import javax.swing.*;
 
public class AgentCallStatusApps extends Applet implements Runnable{

String sAgentExtn = null;
String sAgentId = null;
String sAgentPwd = null;
String servletUrl = null;
String sComp = null;
String msg = null;
String msg1 = null;
String msg2 = null;
String msg3 = null;

String sPCallStatus = "idle";
String sCCallStatus = "idle";
String sInStateTime = "00:00:00";
int iSec = 0;
int iMin = 0;
int iHrs = 0;
String sDate = null;

Thread t = null;
int state;
boolean stopFlag;

public synchronized void init(){
super.init();
    this.setLayout(new BorderLayout());
    this.setBackground(Color.gray);
    this.setForeground(Color.white);
    this.setFont(new Font("Arial", Font.BOLD, 12));
    
    statusMessageCompose();
}


public void start(){
sAgentExtn = getParameter("agentExtn");
sAgentId = getParameter("agentId");
sAgentPwd = getParameter("agentPwd");
servletUrl =  getParameter("servletUrl");

t= new Thread(this);

if(sAgentExtn == null && sAgentId == null && sAgentPwd == null ){
msg = null;
sComp = null;
}else{
sComp =""+sAgentExtn+"/"+sAgentId+"/"+sAgentPwd+"";
}

stopFlag = false;
t.start();
}


public void run(){
char ch;
for(;  :wink:  {
try{
repaint();
Thread.sleep(250);
try{            
// Pass the Request to the Servlet  and get the Value from it
// connect to the servlet
URL sDBservlet = new URL( servletUrl );
URLConnection servletConnection = sDBservlet.openConnection(); 

// inform the connection that we will send output and accept input
servletConnection.setDoInput(true);          
servletConnection.setDoOutput(true);

// Don't used a cached version of URL connection.
            servletConnection.setUseCaches (false);
 
            // Specify the content type that we will send binary data
            servletConnection.setRequestProperty ("Content-Type", "application/x-java-serialized-object");

            // send the ExtnInfo object to the servlet using serialization
        sendCallInfoToServlet(servletConnection, sComp);
                
        // now, let's read the response from the servlet.
        // this is simply a confirmation string
            sCCallStatus = readStatusServletResponse(servletConnection); 
            
            // capture the  PC Time
            getPCDate();  
            
            if(sCCallStatus.equalsIgnoreCase(sPCallStatus)){
            //Show In-State Time
            }else{
            sPCallStatus = sCCallStatus; 
            //re-set you In-State Time 
            }
            
            //Create Status Pane 
            statusMessageCompose();           
            
}catch(Exception e){}

if(stopFlag)
break;

}catch(InterruptedException e){}
}
}


protected void sendCallInfoToServlet(URLConnection servletConnection, String sCom)
    {
        ObjectOutputStream outputToServlet = null;        
        try{       
        outputToServlet = new ObjectOutputStream(servletConnection.getOutputStream());
        
        // serialize the object
        outputToServlet.writeObject(sCom);
        
        outputToServlet.flush();        
        outputToServlet.close();
       
        }catch (IOException e){  }
    }


protected String readStatusServletResponse(URLConnection servletConnection)
    {   String sResult = null;
        BufferedReader inFromServlet = null;     
        try
        {           
        //receive result from servlet
InputStream instr =servletConnection.getInputStream();
ObjectInputStream inputFromServlet = new ObjectInputStream(instr);

sResult = (String) inputFromServlet.readObject();

inputFromServlet.close();
instr.close();           
        }catch (Exception e){  }
        
        return sResult;
    }


    public void getPCDate(){
    Date currentDate = new Date();
SimpleDateFormat formatter = new SimpleDateFormat("dd.MMM.yyyy hh:mm:ss aaa");
sDate = formatter.format(currentDate).toString();
    }    
    
    public void statusMessageCompose(){
    msg = "";
msg +=  "Call Status: [ ";

msg1 = "";
msg1 = sCCallStatus;

msg2 = "";
msg2 += " ]";

msg3 = "";
msg3 = sDate;
    }  

    public void stop(){
stopFlag = true;
t = null;
}    
    
public void paint(Graphics g){

this.setLayout(new BorderLayout());
    this.setBackground(Color.gray);
    this.setForeground(Color.white);  
    
if(msg1 != null){
//Draw Single Line Appearance
g.setColor(Color.white);
g.drawRect(10,5,30,10);

if(sCCallStatus.equalsIgnoreCase("Active")){
g.setColor(Color.green);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}else if(sCCallStatus.equalsIgnoreCase("Ringing")){
g.setColor(Color.red);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}else if(sCCallStatus.equalsIgnoreCase("Talking")){
g.setColor(Color.green);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}else if(sCCallStatus.equalsIgnoreCase("Hold")){
g.setColor(Color.yellow);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}else if(sCCallStatus.equalsIgnoreCase("InUse")){
g.setColor(Color.green);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}else{
g.setColor(Color.blue);
g.fillRect(10,5,30,10);

g.drawString(msg1,130,15);
}

g.setColor(Color.white);
g.drawRect(10,15,30,21);
g.drawString("1",20,31);

//  Draw Status Bar
g.drawString(msg,50,15);
g.drawString(msg2,180,15);
g.drawString(msg3,50,35);

}else{
g.drawString("Please Wait ...|AgentCallStatusApps!",60,10);
}
}
}

Exception in thread "AWT-EventQueue-5" java.lang.NullPointerException: String is null
at sun.java2d.SunGraphics2D.drawString(Unknown Source)
at AgentCallStatusApps.paint(AgentCallStatusApps.java:250)
at sun.awt.RepaintArea.paintComponent(Unknown Source)
at sun.awt.RepaintArea.paint(Unknown Source)
at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
[ July 05, 2007: Message edited by: Ulf Dittmer ]

[Ulf Dittmer]

In which line does the exception occur? What is the value of the string you're trying to draw in that line?

}catch(Exception e){}
}catch (IOException e){ }
}catch (Exception e){ }

Ignoring exceptions is not generally a good idea, and definitely not here. You should put in place some proper error handling.

Note that I have added CODE tags around your code - they make reading it much easier. See UseCodeTags for more information.
[ July 05, 2007: Message edited by: Ulf Dittmer ]