jpa - What to put into jta-data-source of persistence.xml that works on all vendors?

Question

Similar to What to put into jta-data-source of persistence.xml? and How to map jpa datasources in WildFly?

However, I am asking for something that would work on all vendors or at least WildFly, Glassfish/Payara, WebSphere Application Server classic, WebSphere Application Server Liberty, TomEE. I am not looking for something that works in a Java SE Unit test.

So far I found that java:comp/env/jdbc/xxx works in WebSphere Application Server and TomEE. There's a mapping exercise (which is expected) to get it working but I cannot get the same to work on GlassFish/Payara and JBoss/WildFly.

More specifically I do not wish to use default data source because for my scenario I am actually working on two different data sources. E.g. for reference data and another for transactional.

Answer 1

If all of the app servers you work with are Java EE 7 compliant, you can use the default data source, which is required per EE7 spec to be available at:

java:comp/DefaultDataSource

The app server you run on ought to let you customize the configuration of the DefaultDataSource.

Since I'm familiar with WebSphere Liberty, I can point you to this doc for default data sources on Liberty:
Configuring a default data source

If you are using WebSphere traditional, as of v9.0 it supports Java EE 7, and has a default data source available out of the box (under the spec mandated JNDI name).