GWT and OpenJPA not working together

Hi,
I'm trying to implement a UserManagement based on GoogleWebToolkit
(Adding, deleting, assigning privileged; nothing special there). The
GWT-module is using a serparate persistence module, which I included
as a jar-file and which is based on OpenJPA.

The persistence layer is working fine as long is I run it standalone.
But when I wire it to my GWT project, I can't create the
EntityManagerFactory any more. I get a NullPointerException in one of
the OpenJPA classes, which I think is because that Google App Engine
replaced the default java.lang.ClassLoader.

Is it a bad idea to use OpenJPA with GWT? Is there anything to
consider when combining these libraries?

For better understanding find the source code attached.
Any help would be greatly appreciated.
thx, roman

The server is running at http://localhost:8888/
[WARN] Error for /usermgmtui/userInformation
java.lang.ExceptionInInitializerError
at org.apache.openjpa.kernel.Bootstrap.invokeFactory(Bootstrap.java:
116)
at
org.apache.openjpa.kernel.Bootstrap.getBrokerFactory(Bootstrap.java:
96)
at
org.apache.openjpa.persistence.OpenJPAPersistence.getEntityManagerFactory(OpenJPAPersistence.java:
92)
at
com.mycompany.commons.jpa.JpaUserManagement.<init>(JpaUserManagement.java:
64)
at
com.mycompany.commons.UserManagementImpl.setDatasoure(UserManagementImpl.java:
71)
at
com.mycompany.ui.server.UserInformationServiceImpl.<init>(UserInformationServiceImpl.java:
36)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown
Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
at
org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:
428)
at
org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:
339)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
487)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1166)
at
com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:
35)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:
58)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:
43)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:
122)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:
94)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
388)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:
216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:
182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:
765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
418)
at
com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:
70)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at com.google.appengine.tools.development.JettyContainerService
$ApiProxyHandler.handle(JettyContainerService.java:351)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
542)
at org.mortbay.jetty.HttpConnection
$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at
org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
409)
at org.mortbay.thread.QueuedThreadPool
$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.lang.reflect.UndeclaredThrowableException
at $Proxy29.recordAppClassLoader(Unknown Source)
at
com.google.appengine.tools.development.agent.runtime.Runtime.recordClassLoader(Runtime.java:
47)
at
org.apache.openjpa.lib.util.MultiClassLoader.<init>(MultiClassLoader.java:
60)
at org.apache.openjpa.lib.util.J2DoPrivHelper
$47.run(J2DoPrivHelper.java:1011)
at org.apache.openjpa.lib.util.J2DoPrivHelper
$47.run(J2DoPrivHelper.java:1009)
at java.security.AccessController.doPrivileged(Native Method)
at
org.apache.openjpa.lib.conf.ProductDerivations.<clinit>(ProductDerivations.java:
59)
... 44 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.apphosting.utils.clearcast.ClearCast$CasterImpl
$ProxyHandler.invoke(ClearCast.java:411)
... 51 more
Caused by: java.lang.NullPointerException
at
org.apache.openjpa.lib.util.MultiClassLoader.hashCode(MultiClassLoader.java:
277)
at java.util.WeakHashMap.put(Unknown Source)
at
com.google.appengine.tools.development.agent.impl.AgentImpl.recordAppClassLoader(AgentImpl.java:
34)
... 56 more
[WARN] Nested in java.lang.ExceptionInInitializerError:
java.lang.reflect.UndeclaredThrowableException
at $Proxy29.recordAppClassLoader(Unknown Source)
at
com.google.appengine.tools.development.agent.runtime.Runtime.recordClassLoader(Runtime.java:
47)
at
org.apache.openjpa.lib.util.MultiClassLoader.<init>(MultiClassLoader.java:
60)
at org.apache.openjpa.lib.util.J2DoPrivHelper
$47.run(J2DoPrivHelper.java:1011)
at org.apache.openjpa.lib.util.J2DoPrivHelper
$47.run(J2DoPrivHelper.java:1009)
at java.security.AccessController.doPrivileged(Native Method)
at
org.apache.openjpa.lib.conf.ProductDerivations.<clinit>(ProductDerivations.java:
59)
at org.apache.openjpa.kernel.Bootstrap.invokeFactory(Bootstrap.java:
116)
at
org.apache.openjpa.kernel.Bootstrap.getBrokerFactory(Bootstrap.java:
96)
at
org.apache.openjpa.persistence.OpenJPAPersistence.getEntityManagerFactory(OpenJPAPersistence.java:
92)
at
com.mycompany.commons.jpa.JpaUserManagement.<init>(JpaUserManagement.java:
64)
at
com.mycompany.commons.UserManagementImpl.setDatasoure(UserManagementImpl.java:
71)
at
com.mycompany.ui.server.UserInformationServiceImpl.<init>(UserInformationServiceImpl.java:
36)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown
Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
at
org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:
428)
at
org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:
339)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
487)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1166)
at
com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:
35)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:
58)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:
43)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:
122)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:
94)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
388)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:
216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:
182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:
765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
418)
at
com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:
70)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at com.google.appengine.tools.development.JettyContainerService
$ApiProxyHandler.handle(JettyContainerService.java:351)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
542)
at org.mortbay.jetty.HttpConnection
$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at
org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
409)
at org.mortbay.thread.QueuedThreadPool
$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.apphosting.utils.clearcast.ClearCast$CasterImpl
$ProxyHandler.invoke(ClearCast.java:411)
... 51 more
Caused by: java.lang.NullPointerException
at
org.apache.openjpa.lib.util.MultiClassLoader.hashCode(MultiClassLoader.java:
277)
at java.util.WeakHashMap.put(Unknown Source)
at
com.google.appengine.tools.development.agent.impl.AgentImpl.recordAppClassLoader(AgentImpl.java:
34)
... 56 more

java.lang.NoClassDefFoundError: Could not initialize class
org.apache.openjpa.lib.conf.ProductDerivations
at org.apache.openjpa.kernel.Bootstrap.invokeFactory(Bootstrap.java:
116)
at
org.apache.openjpa.kernel.Bootstrap.getBrokerFactory(Bootstrap.java:
96)
at
org.apache.openjpa.persistence.OpenJPAPersistence.getEntityManagerFactory(OpenJPAPersistence.java:
92)
at
com.mycompany.commons.commons.jpa.JpaUserManagement.<init>(JpaUserManagement.java:
64)
at
com.mycompany.commons.commons.UserManagementImpl.setDatasoure(UserManagementImpl.java:
71)
at
com.mycompany.commons.ui.server.UserInformationServiceImpl.<init>(UserInformationServiceImpl.java:
36)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown
Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
at
org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:
428)
at
org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:
339)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:
487)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1166)
at
com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:
35)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:
58)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:
43)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:
122)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
com.google.appengine.tools.development.BackendServersFilter.doFilter(BackendServersFilter.java:
94)
at org.mortbay.jetty.servlet.ServletHandler
$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:
388)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:
216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:
182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:
765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:
418)
at
com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:
70)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at com.google.appengine.tools.development.JettyContainerService
$ApiProxyHandler.handle(JettyContainerService.java:351)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:
152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:
542)
at org.mortbay.jetty.HttpConnection
$RequestHandler.content(HttpConnection.java:938)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at
org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:
409)
at org.mortbay.thread.QueuedThreadPool
$PoolThread.run(QueuedThreadPool.java:582)

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