I'm working with Tomcat, Eclipse and Maven. I added the ObjectDB to the project (libraries > add external jar).

In Eclipse everything seems to be okay. It does not show any "not found" errors and the autocomplete works. But when I run the project it shows this error message:

```
Ljavax/persistence/EntityManager;

viewId=/login.xhtml
location=...
phaseId=RENDER_RESPONSE(6)

Caused by:
java.lang.ClassNotFoundException - javax.persistence.EntityManager
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)

```

Is anything wrong with my implementation?