Question

In my application right now I have one project which contains all the JPA entities. I would like to modularize my application along feature lines:

• Feature1.jar – has all JPA entities for feature 1, business logic, ui logic … etc
• Feature2.jar – has all JPA entities for feature 2, business logic, … etc

How can JPA 2.0 be configured to place the JPA entities in Feature1.jar and Feature2.jar into the same persistence unit?

Answer 1

Use tag <jar-file> in persistence unit

<jar-file>Feature1.jar</jar>
<jar-file>Feature2.jar</jar>  

ear should look like

.ear 
+- /lib 
|  +- persistence.jar
|     +- /META-INF 
|        +- persistence.xml 
+- .war file
+- Feature1.jar
+- Feature2.jar