GWT and an unreproducable 503 error

I have a web-application built with GWT (2.0.3) and run on Apache Tomcat 6.

My application uses long polling to enable client-server conversations. When a client is unable to connect to the server it displays a disconnected message on the page and grays out the controls until it is able to resume conversation with the server.

This happens through the use of the onFailure method of t开发者_JAVA技巧he rpc services; I keep track on how many consequtive exceptions I've received and if it passes a defined threshhold the above scenario happens.

This allows notifying the user of a problem while in the background continuing to resume the server conversation.

This has been the configuration for about 6 months, and without a problem.

I compiled the application after a change and wanted to see it in stand-alone mode so I started up tomcat (not via eclipse) and everything seemed to work fine.

When I ctrl+c'd the apache (while having clients up) I saw the clients displaying a 503 error instead of my app with the disconnected message.

I then tried to reproduce the issue but was unable as the next times the app behaved as expected.

I'm not sure if it's relevant but recently I added an UncaughtExceptionHandler to my module's onModuleLoad.

Has anyone encountered such an issue?

Do you know how I can make my client immune to such an issue?

Thanks a lot,

Ittai

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Probably your app tried to connect to server while it was in process of shutting down. Some of the services might have already shut so the request failed with internal server error.

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I've got similar issue having an apache httpd in front of the tomcat and stopping tomcat while one of the "background" async requests were being made, due to the security redirection policy the failing request ends redirecting the browser and voilà our 503 error page.