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Re: [eclipselink-dev] Loading multiple persistence.xml files

Hi Carl,

What issues are you seeing when you specify several orm files within the same persistence unit definition in one persistence.xml file?


<persistence xmlns=""; xmlns:xsi=""; xsi:schemaLocation=" persistence_1_0.xsd" version="1.0">

    <persistence-unit name="default" transaction-type="RESOURCE_LOCAL">




Carl Hall wrote:
Hi, Tom.

You've nailed it. Each persistence.xml is trying to create the same persistence unit ("default"). Is there a nice way to load 1 persistence unit from multiple orm.xml files? I've seen some classloader tricks to accomplish this but don't want to head down that rabbit hole unless necessary.


On Wed, Dec 17, 2008 at 10:55, Tom Ware <tom.ware@xxxxxxxxxx <mailto:tom.ware@xxxxxxxxxx>> wrote:

    Hi Carl,

     Are you using separate EntityManagers for each persistence unit?

     An EntityManager represents one persistence unit - when the
    EntityManagerFactory is created, you get it by persistence unit
    name.  Any EntityManager created by that factory will represent that
    persistence unit.

     The name of a persistence unit is specified in the persistence.xml
    and only one persistence.xml may be used to define a given
    persistence units.  It is an error to have multiple persistence.xml
    that define the same persistence unit and the behavior is undefined
    - I am not surprised that if you are doing this, you get the last
    one loaded.

     To access different persistence units, create an EntityManager for


    Carl Hall wrote:

        I have a setup where multiple project come into a shared
        classloader.  Each project can have its own model files and
        thusly its own persistence.xml and orm.xml files.  When I create
        an EntityManager, I see in the logs that each persistence.xml
        file is found (3) and each orm.xml file loads with the expected
        entities.  When I try to query or persist using this
        EntityManager, only the entities from the lastly loaded
        persistence.xml is found.  Am I loading this correctly?  Am I
        trying to access things incorrectly?


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