jndi database connection with jpa and eclipselink

Question

I try to setup a database connection in java with JNDI in combination with eclipseLink/JPA on Tomcat 5.5. I already configured the JNDI resource in web.xml and context.xml.

Answer 1

Year 2015 actualisation: I not sure Eclipselink SessionCustomizer is required. In my test all work without (Tomcat 7.x, Java 7.x, Eclipselink 2.4.x).

Some older materials suggest specific problem with Tomcat 5/6 and special way to resolve it.