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»Forums Index »Archive (2017 and earlier) »IQFeed Developer Support »Java RemoveClientApp() call not working in
Author Topic: Java RemoveClientApp() call not working in (4 messages, Page 1 of 1)

-Interested User-
Posts: 28
Joined: Apr 9, 2005

Posted: Nov 8, 2006 12:34 PM          Msg. 1 of 4
Just upgraded my code from version 2.x to the IQFeed Developer, version and the RemoveClientApp() method fails to close the DTN App. I'm concerned, since this used to work.

I am connecting from Java using the TCP/IP method (code will follow). I use the RegisterClientApp() and then get a new socket. On disconnect, I call the RemoveClientApp() method. In the past calling RemoveClientApp() closed the socket the the DTNApp in the system tray. The new version does close the socket, but does not close the App.

The issue comes up when either I lose a connection to DTN, or when I automatically start and stop the Connection. If you attempt a reconnect with the disconnected DTNApp still resident, I get "Application Already Exists" error.

Anyone know what I am doing wrong?

public class IQConn extends IQ_32
//connection status parameters
int a, b;
Socket dtnSocket;
BufferedReader sin;
BufferedWriter sout;

public void connect()
RegisterClientApp( "IQFEED_DEMO", "1.0", "0.11111111" );
if( a != 0 || b != 0 ) return;

dtnSocket = new Socket( InetAddress.getByName( "localhost" ), 9100 );
sin = new BufferedReader( new InputStreamReader( dtnSocket.getInputStream() ) );
sout = new BufferedWriter( new OutputStreamWriter( dtnSocket.getOutputStream() ) );
catch( Exception e )


public void disconnect()

-DTN Guru-
Posts: 2093
Joined: Nov 21, 2005

Posted: Nov 8, 2006 04:12 PM          Msg. 2 of 4
I have been able to duplicate this issue in version

Your app is not properly being registered as a client in IQConnect. As a result, when your app closes, IQConnect isnt able to determine that it is time to shut itself down.

As a workaround, all you have to do is maintain a Level1 socket connection while your app is running. This will cause your java app to be properly registered as a client with IQConnect and will properly close when the level1 connection closes.

We will look into this functionality make changes as necessary in a future release.
Edited by DTN_Steve_S on Nov 8, 2006 at 04:13 PM

-Interested User-
Posts: 28
Joined: Apr 9, 2005

Posted: Nov 8, 2006 05:11 PM          Msg. 3 of 4
Thanks for the quick response: couple of follow-up questions:

1. I followed the Java example to register my client. Can you see what I am doing incorrectly in the above code?
2. The socket is the issue for us. Sometimes it just dies, which is why we are trying to relaunch the app. Are you implying that we should check that the socket is closed, and if it is create a new one?
3. Finally, what is a Level 1 socket? Is that a Financial term (level 2, etc) or a network term?

-DTN Guru-
Posts: 2093
Joined: Nov 21, 2005

Posted: Nov 8, 2006 05:32 PM          Msg. 4 of 4
1) From what I can tell, this is not a problem with your code.

2) When this dies, is a relaunch required or can you start another instance of your app and recieve data through that one? I am not suggesting this as a "workaround", I am simply asking this for troubleshooting purposes.

3) By "Level 1 socket" I am referring to a regular tcp socket connection to the Level1 port in IQConnect. All apps should maintain a connection to this port throughout the time they are active. All status updates are sent to the client via the level 1 port.


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