Question

I have a litte web app which works properly when deployed to the App Engine in Eclipse.
However, I get an error when I want to deploy my app to my Tomcat server.

I copied the content of my war folder directly to the default ROOT folder of Tomcat.
Then I run my app on an external server inside Eclipse.

Everything works fine to that point – the app is loaded straight from the browser’s cache.

Here comes the problem:

The google chrome development console says “Uncaught ReferenceError: function is not defined” when I click on some features of my app that are realized through JSNI on GWT side.
I understand that the error comes from a JS caller inside external JS code. The caller invokes a GWT client-side method/function (that’s why it is not defined in the ext. JS code).

Any suggestions on how to solve this problem?

Answer 1

Do you have any extra modules that require external js files? Some modules require the js files to be included in the war and included in your root .html file. It could be the case that you are using a library that doesn’t have the base js functions.

You can add this to your .gwt.xml file to turn on the stack trace.

<set-property name="compiler.stackMode" value="emulated"/>
<set-configuration-property name="compiler.emulatedStack.recordLineNumbers" value="true"/> 
<set-configuration-property name="compiler.emulatedStack.recordFileNames" value="true"/> 

You could also try the setUncaughtException handler to see exceptions that are being thrown in production mode. With the emulated stack trace turned on you should be able to get a backtrace that has line numbers for your code. It is not as good as development mode but very useful for debugging.

GWT.setUncaughtExceptionHandler(new GWT.UncaughtExceptionHandler()) {
    @Override
    public void onUncaughtException(Throwable cause) {
        logger.log(Level.SEVERE, "OOPS", cause);
    }
}

Note Make sure your logger is configured to use something you can access. Like firebug or remote logging servlet.

I currently use tomcat 7 in production and development mode using eclipse. You can configure a tomcat instance of the server in eclipse and use the “Run as WebApplication on External Server”. This will allow you to see the exception in development mode.

Also make sure you don’t have the ?gwt.codesvr=127.0.0.1:9997 if you are in production mode. This will cause problems too unless you have the development code server running.