Why this application hangs up?

[arun mahajan]

Hello Everybody,
I have made following four files for my application..this application is suppose to do following:-
1. This will run on my local Network.
2. It will behave as server and will accepts request from different clients.
3. After receving a request it will process the same and will send to another machine on same network.
4. This "another machine" after receving will send back a response.
5. My application will output as per its response.
I have made following four files:
1. MultiServer : This will listens all request
2. MultiServerThread: this will process the request.
3. MultiProtocol: It declares every commonly used variables.
4. Mc: This will interects with my "another machine".
My problem with this application is that:-
1. It sometimes hangs and will start if I press "Ctrl+C" instead of terminating it.
2. Sometime it never provide a response back from the read method of Mc file.

I am in a fix & don't know a reason for it .. could you please help me?
P.S.: I apologise for such a long Thread..but i don't know how else can I put my code here
regards,
Arun

[B]MultiServer.java[/B]
package Server.t2;
import java.net.*;
import java.io.*;
public class MultiServer extends MultiProtocol
{
Mc mc = null;
    public static void main(String[] args) throws IOException {
        boolean listening = true;
MultiServer multiserver=new MultiServer();
multiserver.start();
while(listening)
{
if(mcStatus>0)
{
System.out.println("Please Wait restarting server.....");
multiserver.varNull();
multiserver.restartServer();
}
try
{
System.out.println("\n Waiting for another request....");
Socket client = serverSocket.accept();
if(client!=null)
{
Thread t=new Thread(new MultiServerThread(client,multiserver.mc));
t.setDaemon(true);
t.start();
}
client = null;
}
catch(IOException e)
{
mcStatus = 1;
System.out.println("Error while accepting the client : "+e);
}
catch(Exception e)
{
mcStatus = 1;
System.out.println("Error while accepting the client : "+e);
}
}//while
        serverSocket.close();
    }
public void restartServer()
{
mc = new Mc();
mc.connect_mc();
while(login_mc_val)
{
varNull();
waitServer();
mc.connect_mc();
}
if(login_mc_val)
startLocalServer();
else
{
System.out.println("Sorry!! Server could not be started as Login Failed");
varNull();
System.exit(1);
}
}
public void start()
{
mc = new Mc();
mc.connect_mc();
if(login_mc_val)
startLocalServer();
else
{
System.out.println("Sorry!! Server could not be started as Login Failed");
varNull();
System.exit(1);
}
}
public synchronized void waitServer()
{
try
{
wait(5*60*1000);
}catch(InterruptedException e)
{
System.out.println("Error in waiting: "+e);
}
}
public void startLocalServer()
{
try
{
serverSocket = new ServerSocket(8888);
}
catch (IOException e)
{
System.err.println("Could not listen on port: 8888.");
varNull();
System.exit(1);
        }
}
public void varNull()
{
if(mc!=null)
mc.varNull();
serverSocket=null;
}
public void destroy()
{
if(mc!=null)
mc.varNull();
serverSocket=null;
}
}

[B]MultiProtocol.java[/B]
package Server.t2;
import java.net.ServerSocket;
import java.net.Socket;
import java.io.DataInputStream;
import java.io.DataOutputStream;
public abstract class MultiProtocol
{
public static DataInputStream dis = null;
public static DataOutputStream dos = null;
public static ServerSocket serverSocket = null;
public static Socket mcSocket = null;
public static boolean mc_connect_val = false;
public static boolean login_mc_val = false;
public static String sub_msg="";
public static int mcStatus=0;
public final String STX = new String(new Character((char)2).toString());
public final String ETX = new String(new Character((char)3).toString());
}

[B]MulitServerThread.java[/B]
package Server.t2;
import java.net.*;
import java.io.*;
public class MultiServerThread extends MultiProtocol implements Runnable
{
private Socket client = null;
private ObjectInputStream ois = null;
private ObjectOutputStream oos = null;
static int msg_no=1;
Mc mc = null;
    public MultiServerThread(Socket client,Mc mc)
    {
this.client = client;
this.mc = mc;
    }
    public void run()
    {
if(client != null)
{
msg_no = msg_no+2;
readLocal(msg_no);
}
}
public void start()
{
run();
}
public synchronized void readLocal(int msg_number) //this is to read servlet instructions
{
String ret_str = "";
String input_str = "";
try
{
InputStream in = client.getInputStream();
ois = new ObjectInputStream(in);
OutputStream out = client.getOutputStream();
oos = new ObjectOutputStream(out);
input_str = new String();
input_str = (String)ois.readObject();
}
catch(IOException e)
{
System.out.println("Error in reading Object for call: "+msg_no+" : "+e);
}
catch(Exception e)
{
System.out.println("Error in reading Object for call: "+msg_no+" : "+e);
}
if((input_str != null) && (input_str.length()>=1))
{
System.out.println("String Received for msg "+msg_no+" : "+input_str);
if(input_str.indexOf("90:")>=0)
{
FindMsg(msg_number);
ret_str = submit_1(sub_msg);
}
else
{
FindMsg(msg_number);
ret_str = submit_2(sub_msg,input_str);
}
}//if for checking user authetication
else
{
ret_str="String failed";
}
writeLocal(ret_str);
notifyAll();
ret_str=null;
input_str=null;
varNull();
System.gc();
}
public synchronized void writeLocal(String ret_str1)
{
try
{
oos.writeObject(ret_str1);
oos.flush();
}
catch (Exception e)
{
System.out.println("Error in writeLocal: "+e);
}
}//writeLocal
public synchronized void FindMsg(int msg_number)
{
if(msg_number<10)
{
sub_msg="00"+msg_number;
}
else if (msg_number<100)
{
sub_msg="0"+msg_number;
}
else if(msg_number<500)
{
sub_msg=""+msg_number;
}
else if(msg_number>=500)
{
msg_no=1;
msg_number=msg_no;
sub_msg="00"+msg_number;
}
}
public synchronized String submit_2(String mno,String message)
{
String submit_val = "";
String submit = STX + ""+mno+"\t"+message+"\t"+ETX;
submit_val = mc.write(submit,"submit");
return submit_val;
}
public synchronized String submit_1(String mno)
{
String submit_val = "";
String submit = STX + "90:"+mno+"\t"+ETX;
submit_val = mc.write(submit,"submit");
return submit_val;
}
public void varNull()
{
try
{
ois.close();
oos.close();
}catch(IOException e)
{
System.out.println("Error in closing ois & oos"+e);
}
ois=null;
oos=null;
client=null;
}
public void destroy()
{
try
{
ois.close();
oos.close();
}catch(IOException e)
{
System.out.println("Error in closing ois & oos"+e);
}
ois=null;
oos=null;
client=null;
}
}

[B]Mc.java[/B]
package Server.t2;
import java.net.*;
import java.io.*;

public final class Mc extends MultiProtocol
{
public Mc() {}
public synchronized String read(String msg) throws IOException
{
String retVal = new String();
retVal="";
byte[] buf = new byte[500];
dis.read(buf);
for(int i=0;i<500;i++)
{
char ch = (char)buf[i];
retVal += ch;
}//for
retVal = retVal.trim();
buf = null;
System.out.flush();
return retVal;
}
public synchronized String write(String sendVal,String str)
{
String read_val = "";
try
{
dos.write(sendVal.getBytes());
dos.flush();
read_val = read(str);
int i=0;
}
catch (IOException e)
{
String msg = "Error in Write: "+e;
e.printStackTrace();
read_val +=msg;
mcStatus = 1;
}
return read_val;
}//write
public synchronized void login()
{
String login = STX+"login"+ETX;
String return_val = write(login,"login");
if((return_val.indexOf("Error")>=0))
{
login_mc_val=false;
}
else
{
login_mc_val=true;
}
login = null;
}//login
public synchronized void connect()
{
try
{
mcSocket = new Socket("192.168.100.100",8899);
if(mcSocket != null)
{
dos = new DataOutputStream(mcSocket.getOutputStream());
dis = new DataInputStream(mcSocket.getInputStream());
mc_connect_val =true;
System.out.println("Connected...");
}
}
catch (Exception e)
{
System.out.println("Error in connecting : "+e);
mc_connect_val = false;
}
}//connect
public synchronized void connect_mc()
{
varNull();
if(!mc_connect_val)
connect();
if((!login_mc_val) && mc_connect_val)
login();
}
public void varNull()
{
try
{
mc_connect_val = false;
login_mc_val = false;
mcStatus=0;
if(mcSocket != null)
{
dos.close();
dis.close();
}
mcSocket=null;
dos=null;
dis=null;
}
catch(Exception e){}
}
public void destroy()
{
try
{
mc_connect_val = false;
login_mc_val = false;
mcStatus=0;
if(mcSocket != null)
{
dos.close();
dis.close();
}
mcSocket=null;
dos=null;
dis=null;
}
catch(Exception e){}
}
public static void main(String[] s)
{
Mc mc=new Mc();
mc.connect_mc();
}
}

[Mr. C Lamont Gilbert]

Could you show your test procedure?
Which computers start what processes, and in what order?
Thanks.

[arun mahajan]

The objective here is to listenes from any computer from the same network at a computer which will run this MultiServer application..This after recieving a call will process this call and will send it to "another machine"..which in trun sending a response back at the time of accepting any request..
So that means this computer which is running MultiServer aplication will keep on listening the request from various computer..

So I am trying to send too many request at same time from various computer at this MultiServer computer and accepting it to respond me back..
Can you find a reason?
regards,
Arun

[Mr. C Lamont Gilbert]

What I want you to say is
First I start the server on Computer A
second I start a client on Computer B
third I start so and so on Computer C
I know your objective I think, but what I want is your testing procedure. I personally made a MessagePassingInterface type of program in RMI so I am familiar with some of these issues. But without knowing how you are testing its hard to know wher to look for the problem.

[arun mahajan]

I apologise if following answer could not explain what you're looking for. I would like to request you to find some more time and explain me your needs in more details in that case.
Procedure is as folows:
1. First I run a program from Third Party vendor which is running on my server. Say Machine A
2. Than i run my MultiServer program runs on another machine say machine B
3. After running these two programs now i try to sends requests from various client machine to machine B and trying to observe the result back on Client.
4. there are about 35 computers on this network and they can sends there request to machine B.
5. That means all above 4 programs are running on machine.
Need is:
Client should send a request which will land on machine B this will in turn sends request to machine A. Machine A will send back a response to machine B and machine B will than sends a response based on this to client back

Hope this will explain the procedure of my testing
procedure.
Pl let me know your comments.
regards,
Arun

[arun mahajan]

Do I need to provide some more information for same...
Can you help me debug it ?
regards,
Arun

[arun mahajan]

Oops...perhaps I am giving less information to attract JGurus to answer for this posting...or perhaps this is something stupid to ask for..
Could you please let me know your comments?
PLEASE HELP ME TO SORT THIS ISSUE.
regards,
arun

[arun mahajan]

OOps..still this thread is being unanswered..can it attracts somebody's eye..let me know if any additional info reqd to solve this issue..
Any help me be highly appreciated..
regards,
Arun

[Mr. C Lamont Gilbert]

I understand your processs now.
Since you are starting a couple of different JVMs here, exactly which one is locking up and forcing you to press ctrl-C in order to continue? And where in the process does it lock up?