Design pattern for modular application (how to reuse entities)

I have the following scenario:

1. A JAX-RS Webservice that is responsable for the business logic and database interactions.


2. A webapp that will be used by the end users.


3. A webapp that will be used by administrators.

My problem is that I want to reuse the entities from the webservice on the other apps, but it is highly wrapped with frameworks like JPA, JAX-RS, CDI, among others... So I am having a hard time to isolate them. What I want is to know the best workaround and why should I use it instead of others.