[equinox-dev] [prov] Strange error message: org.osgi.framework.BundleExc

[Stefan Liebig <Stefan.Liebig@xxxxxxxxxxxx>]

I started to refactor SimpleArtifactRepositoryFactory to use 
ECFTransport instead of using URL.openStream() to load the artifacts.xml.
In my first attempt I was using ECFTransport to download artifact.xml 
into a temporary file and than reading its content with 
SimpleArtifactRepositoryIO. This worked very well (I used ProvAdminUI 
for testing) but I didn´t like the temporary file storage. My second 
attempt was to use a PipedInput/Ouputstream pair to do that. Therfore I 
start a download thread which uses ECFTransport pushing into the 
PipedOutputStream and the linked PipedInputStream is read by 
SimpleArtifactRepositoryIO.
When I now start ProvAdminUI I got the following error message:

!ENTRY org.eclipse.osgi 2 0 2007-12-17 08:32:25.687
!MESSAGE While loading class 
"org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport$1", 
thread "Thread[Thread-2,6,main]" timed out waiting (5000ms) for thread 
"Thread[main,6,main]" to finish starting bundle 
"initial@reference:file:../../projekte/rcp/org.eclipse.equinox.p2.artifact.repository/ 
[17]". To avoid deadlock, thread "Thread[Thread-2,6,main]" is proceeding 
but "org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport$1" 
may not be fully initialized.
!STACK 0
org.osgi.framework.BundleException: State change in progress for bundle 
"initial@reference:file:../../projekte/rcp/org.eclipse.equinox.p2.artifact.repository/" 
by thread "main".
   at 
org.eclipse.osgi.framework.internal.core.AbstractBundle.beginStateChange(AbstractBundle.java:1139)
   at 
org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:259)
   at 
org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:400)
   at 
org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:111)
   at 
org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:419)
   at 
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:189)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findLocalClass(BundleLoader.java:344)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:412)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:373)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:361)
   at 
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
   at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport.transfer(ECFTransport.java:72)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport.download(ECFTransport.java:67)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.simple.SimpleArtifactRepositoryFactory$Transporter.run(SimpleArtifactRepositoryFactory.java:68)
Caused by: 
org.eclipse.osgi.framework.internal.core.AbstractBundle$BundleStatusException
   ... 16 more
Root exception:
org.eclipse.osgi.framework.internal.core.AbstractBundle$BundleStatusException
   at 
org.eclipse.osgi.framework.internal.core.AbstractBundle.beginStateChange(AbstractBundle.java:1139)
   at 
org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:259)
   at 
org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:400)
   at 
org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:111)
   at 
org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:419)
   at 
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:189)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findLocalClass(BundleLoader.java:344)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:412)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:373)
   at 
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:361)
   at 
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
   at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport.transfer(ECFTransport.java:72)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.ECFTransport.download(ECFTransport.java:67)
   at 
org.eclipse.equinox.internal.p2.artifact.repository.simple.SimpleArtifactRepositoryFactory$Transporter.run(SimpleArtifactRepositoryFactory.java:68)

It seems that is not possible to load the ECF class 
IFileTransferListener within a thread (this happens at 
ECFTransport.java:72).
The Activator of o.e.e.p2.artifact.repository creates the 
ArtifactRepositoryManager which does a restoreRepositories() in its 
constructor. This causes an attempt to create a SimpleArtifactRepository 
which than fails with the above error. When I delay the 
restoreRepositories() until it is really needed than the error does no 
longer occur.
It seems that there is a difference between loading a class (from 
another bundle) from the ´main´ thread and from a spawned thread while 
activating a bundle.
What is the difference?

Stefan