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EclipseLink project works in one Eclipse Workspace but not in another [message #385175]

Fri, 09 January 2009 19:03

Eclipse User

Hi,

I have a very small EclipseLink example which runs perfectly in a
workspace.

I imported this example in another workspace (same Eclipse installation
therefore same version, available plug-ins, etc.) and it did not work.

The following message was issued:

Exception in thread "main" javax.persistence.PersistenceException: No
Persistence provider for EntityManager named people
at
javax.persistence.Persistence.createEntityManagerFactory(Per sistence.java:89)
at
javax.persistence.Persistence.createEntityManagerFactory(Per sistence.java:60)
at de.vogella.jpa.eclipselink.main.Main.main(Main.java:18)

After lots of checking the only difference I could find is that the
second workspace is in a deep folder structure, something like:
C:\Documents and
Settings\vogella\Desktop\Documents\08_MyDocuments\20_Documen tation\JPAPersistenceExamples\de.vogella.jpa.eclipselink2\sr c\META-INF

I imported the project into a thrid workspace with a shorter path (again
same Eclipse installation) and it did work.

Are there any restrictions in relation to the path name or are there any
other reasons why the project does not run in the second workspace?

Best regards, Lars

--
Lars Vogel
http://www.vogella.de/eclipse.html - Tutorials about Eclipse
http://www.vogella.de/articles/RichClientPlatform/article.ht ml - Eclipse
RCP Tutorial

Re: EclipseLink project works in one Eclipse Workspace but not in another [message #385179 is a reply to message #385175]

Sun, 11 January 2009 20:00

Eclipse User

The failing project has spaces in the path. We have fixed a similar issue
in 1.1 and I believe 1.0.2.

What version of EclipseLink are you using.
--Gordon

Re: EclipseLink project works in one Eclipse Workspace but not in another [message #385180 is a reply to message #385179]

Mon, 12 January 2009 05:36

Eclipse User

Hi Gordon,

For this example I'm using eclipselink-1.0.2.

I did try this example in a workspace which had also spaces (but a
shorter path name) and it worked.

The path in which the example is working: is
C:\Documents and
Settings\vogella\Desktop\Documents\08_MyDocuments\14_Eclipse _Test_Path\de.vogella.jpa.eclipselink

The none working path is:
C:\Documents and
Settings\vogella\Desktop\Documents\08_MyDocuments\20_Documen tation\JPAPersistenceExamples\de.vogella.jpa.eclipselink

Best regards, Lars

Gordon Yorke wrote:
> The failing project has spaces in the path. We have fixed a similar
> issue in 1.1 and I believe 1.0.2.
>
> What version of EclipseLink are you using.
> --Gordon
>

--
Lars Vogel
http://www.vogella.de/eclipse.html - Tutorials about Eclipse
http://www.vogella.de/articles/RichClientPlatform/article.ht ml - Eclipse
RCP Tutorial

Re: EclipseLink project works in one Eclipse Workspace but not in another [message #385184 is a reply to message #385180]

Mon, 12 January 2009 15:44

Eclipse User

Hi,

this seesm to be a bug in the Java Classloader (Java 6 Update 11). I
created the following example to demonstrate it:

---------------
package de.vogella.jpa.bug;

import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;

public class Test {
public static void main(String[] args) {
ClassLoader currentLoader = Thread.currentThread()
.getContextClassLoader();
try {
Enumeration<URL> resources = currentLoader
.getResources("META-INF/persistence.xml");
while (resources.hasMoreElements()) {
System.out.println("Elements found");
resources.nextElement();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

----------

Running this in a project with a medium sized path name delivers a hit.
Running it in a project with a long path name return nothing.

I'll open a bug at Sun.

Best regards, Lars

Re: EclipseLink project works in one Eclipse Workspace but not in another [message #385243 is a reply to message #385184]

Wed, 14 January 2009 11:26

Eclipse User

Lars,
Hi, just a reference about 1.6 releases to keep in mind.
The implementation of releases post 1.6.0_07 differ in their
ClassLoader behavior.
We had a classLoader issue in SDO recently where when we loaded >5000
classes the JVM slowed down by a factor of 300+. It turned out that this
behavior only appeared from 1.6.0_01 to 1.6.0_07, when we used a 1.5 JRE
or the 1.6.0_10 JRE there was no issue. It looked like the ClassLoader
implementation in the 1.6.0_10+ JRE's may use a different improved HotSpot
JVM.

See our tracking bug...
https://bugs.eclipse.org/bugs/show_bug.cgi?id=248019

For the SUN bug...
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6763424
Duplicated to
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6471009

thank you
/michael

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