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Home » Eclipse Projects » EclipseLink » Separate project trouble(I have a separate EJB and JPA project both included in EAR)
Separate project trouble [message #665658] Fri, 15 April 2011 12:03 Go to next message
Neikius Mising name is currently offline Neikius Mising nameFriend
Messages: 43
Registered: April 2011
So in short:

Latest eclipse 3.6
Glassfish 3.1 integrated

All gotten from within the eclipse and latest versions.

Now, I can get JPA to work in a single project,but when I put the persistence in one project and EJB in another I cannot ever make the EntityManager to appear.

Also there is a plethora of weird InvalidState errors and debugger desynchs that can be solved only by restarting and redeploying.

But to focus, the thing is set up as such:
* JPA project with classes and persistence.xml
* EJB project that does stuff
* JSF project
* EAR project including all

Whenever I get to a point that would invoke the EntityManager I see that it is null.

I use
EntityManager em;

in EJB

and I have this
public class UserDatabaseEntityManager {
	private EntityManager em;

somewhere. I have tried putting the latter in both projects and it does not work in either, no EntityManager ever comes from the server. I guess I am doing something wrong here but I saw a few sources claiming this should be enough, obviously aint for my setup.

I guess this example was wrong or something but anyway, what would be the proper way of doing it then? I'd like to modularize stuff and take advantage of the jpa /ejb facilities.

Also currently I have in persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="" xmlns:xsi="" xsi:schemaLocation="">
	<persistence-unit name="name" transaction-type="RESOURCE_LOCAL">
		<class>...class here </class>
			<property name="javax.persistence.jdbc.url" value="url here"/>
			<property name="javax.persistence.jdbc.user" value="user"/>
			<property name="javax.persistence.jdbc.password" value="pass"/>
			<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>

Also tried to use the JTA facility here and define jdbc connection and pool on the server and that way doesn't work at all for me not even in a simple project.

Is there anything I am obviously doing wrong? It is apparent I am starting a lot of new stuff here at once, but heck at least this should have been simple no? Its problematic when you don't even have a tutorial that could help me... hence any help much appreciated.
Re: Separate project trouble [message #665698 is a reply to message #665658] Fri, 15 April 2011 14:27 Go to previous messageGo to next message
Shaun Smith is currently offline Shaun SmithFriend
Messages: 197
Registered: July 2009
Senior Member
A few comments:

1. You should be using JTA transaction type and datasource.

2. Are you sure the projects are correctly constructed? The EJB module should be able to see the JPA (utility) jar.

3. I'd recommend trying a simple two project JPA/EJB test using just @PersistenceUnit or @PersistenceContext.


[Updated on: Fri, 15 April 2011 14:28]

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Re: Separate project trouble [message #666100 is a reply to message #665658] Tue, 19 April 2011 07:06 Go to previous message
Neikius Mising name is currently offline Neikius Mising nameFriend
Messages: 43
Registered: April 2011
I got this weird error
javax.servlet.ServletException: Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.2.0.v20110202-r8913): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform 

but then I somehow managed to punch through in a test project no.2... I guess its all about the settings. And the finese must play a large part too, so its not really all that friendly for someone trying for the first time.

I can get something to work, add a few things and I have to retrace and retry a few times to get even the most basic programs through.

So I will take your advice:
1) Always JTA, I guess I botched at jumping to more advanced ways of managing persistence context, gone back to the roots and it works now.

2) Still have trouble here though, for now I have persistence.xml in ejb bean, can I just put it into the jpa utility jar? It was my original intention to do this, but do I have to export the jar and include it? I was thinking of just referencing the jpa project under java build path of the ejb project. Om, seems to work now too, at least in my test project. And I don't have a clue how since I've been doing much the same thing for a while now. I guess I will have to figure this out.

3) Ye, this solved it for me. Not that my project was much more complex, but I guess @PersistenceContext is simpler than @Injecting produced EntityManager, though that should still works simply from what I gather...

Thanks for now, hope I can start with this finally.

edit: Om, I still cannot debug the main project. If I set a breakpoint in EJB it gets hit but I cannot step by step the execution after that... any clues regarding this?

edit2: So, any ideas why do I randomly get that null null errors? Then I just refresh a few times and a few of them it works and a few I get nulls... (nulls to datasource? what?)

[Updated on: Wed, 20 April 2011 08:41]

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