Webapp-jpa-hibernate is a project mainly written in Java, it's free.
Hibernate / JPA / Postgres with simple servlets + JSTL web application demo.
Provide an integrated Hello World application demonstrating JPA persistence using Hibernate and PostgreSQL, in the context of a very simple web application. This demo does not use any real frameworks except for JSTL for a little bit of JSP processing.
This pattern should not be used for all but the simplest possible use cases. However, it's useful to have as a skeleton starting point for a java web application when you don't want to incorporate the complexities of an actual web framework.
Assuming you have setup your postgres database separately and have updated persistence.xml to point at it...