Maybe a very basic question: How to use Tomcat + Hibernate + JPA?

Currently, I'm using Tomcat with plain hibernate with a ServletContextListener that initializes the hibernate configuration programmatically and a one-session-per-request approach as described here https://www.hibernate.org/43.html.

Is there an easy way to enable to use tomcat and hibernate inside of JPA or do I need a full J2EE server to do so?

You absolutely don't need a J2EE server to use hibernate with JPA approach within tomcat.
Just deploy your hibernate application as servlet within tomcat.

N.B.: Maybe you are confusing JPA with JTA ? (JTA is usually used on J2EE servers)

Thanks for your answer and yes, maybe I'm confused :)

In this post (https://forum.hibernate.org/viewtopic.php?f=1&t=1000680) I asked why the callbacks are not supported and mmerder answered:
"Are you using JPA or plain hibernate?" and "Well, It's been a long time since I used plain hibernate and not JPA in a container. But as far as I remember, the entity listeners only work in a JPA environment."

That's where my confusion come from... Can you please help me out :) ? Is JPA a complete different system? As far as I know Hibernate is a JPA implementation, isn't it?

JPA is a standard specification for persistence made by the Java_Community
http://en.wikipedia.org/wiki/Java_Community_Process
and Hibernate is since longer time (I believe since version 3) an implementor of JPA.



I would say no.
The main access class with JPA is the entitymanager whilst with plain 'old-style' hibernate it is the session.
Both classes have very similiar methods and it is also allowed to use both interfaces contemporaneosly,
as most implementation behind JPA delegates to plain hiberante


As you use annotations, like @PreRemove, @PostRemove you have to use the JPA approach (persistence.xml)
or AnnotationConfiguration in order that your annotation are properly parsed.
With old-style hibernate configuraton it may happen that only hbm-files are be parsed whilst your annotations are ignored. I suppose this is the reason why mmerder asked you if you are using JPA or plain hibernate?