Managing EntityManager lifecycle when using JPA in a non enterprise environment (e.g. Tomcat) is a custom task you must take care of by yourself for you don't have the IoC (dependence injection) of a Java EE 5 to manage the EntityManager lifecycle.

Here is a little project to be included as a library in your web applications which don't use a EJB container.

For Configuring your web application to use this library you just need to add a listener and, optionally, the name of the persistence unit to use as an init parameter in your web.xml such as:

``` es.claro.persistence.PERSISTENCE_UNIT MyPersistenceUnit

ServletContext and Request Listener for managing EntityManager with request scope es.claro.persistence.PersistenceAppRequestListener
```

You can omit the init parameter and thus set it programmatically: PersistenceManager.setPersistenceUnit("MyPersistenceUnit");

If no persistence unit name is provided (neither as an init parameter nor programmatically), "DefaultPU" is assumed.