Run hangs on classes from my API

I’ve put mi APIs.jar in the project’s properties ‘Java Build Path’ and copied them in API/WebContent/WEB-INF/lib.
Eclipse Indigo can compile.
At run I raise an exception ’

With that explanation it’s hard to say what your problem is. However, sounds that is not a Vaadin related issue.

I canot give more explanation because I’m not able to understand why Eclispe can compile and prepare the web job, and why, at run tomcat cannot pick the class from my API.jar.
In other words, even if it is not a true vaadin problem, where the jar compiled from my API have to be put in Eclipse ‘Project Explorer’ to be seen by tomcat, or, is any unknown parameter to put in web.xml for make the program working?
In hope to be be more readable, despiste my poor english,
Best regards from PARIS

A precision : my API (Java 1.6 & OODB db4o) is developped outside the vaadin project, and I would link it in a rich client API for presentation.

The stack trace related to the NullPointerException helps you to find out the cause for the exception. But a NullPointerException doesn’t mean that your doesn’t compile. It’s an exception you get at runtime. In short, a NPE means that you have a variable which value is null and you are trying to use it, for example:

TextField tf = null;
tf.getValue(); // This will throw a NPE


Hi Henri,

Thousands thanks.
You are rignt, it was so evident as it blinded me and as I had the other annoyances, I did not know how to see the real problem.

With you help, I have published my first API (just a tool to compute different control keys, the level upper after “Hello World”) with vaadin!

Best regards