We are getting NullPointerExceptions in MRUMemmoryStore when under load.  This
should not be.  The keys looked up are the XSP logicsheets, and this is the
Exception stacktrace available.

ERROR   99504   [cocoon  ] (Thread-40): Error in MRUMemoryStore!

java.lang.NullPointerException

	at org.apache.cocoon.components.store.MRUMemoryStore.checkSeriazable(MRUMemoryStore.java:349)

	at org.apache.cocoon.components.store.MRUMemoryStore.free(MRUMemoryStore.java:337)

	at org.apache.cocoon.components.store.MRUMemoryStore.hold(MRUMemoryStore.java:242)

	at org.apache.cocoon.components.store.MRUMemoryStore.store(MRUMemoryStore.java:227)

	at org.apache.cocoon.components.language.markup.AbstractMarkupLanguage.configure(AbstractMarkupLanguage.java:132)

	at org.apache.avalon.excalibur.component.DefaultComponentFactory.newInstance(DefaultComponentFactory.java:108)

	at org.apache.avalon.excalibur.component.DefaultComponentHandler.get(DefaultComponentHandler.java:92)

	at org.apache.avalon.excalibur.component.ExcaliburComponentSelector.select(ExcaliburComponentSelector.java:246)

	at org.apache.cocoon.components.language.generator.ProgramGeneratorImpl.load(ProgramGeneratorImpl.java:230)

	at org.apache.cocoon.generation.ServerPagesGenerator.setup(ServerPagesGenerator.java:153)

	at org.apache.cocoon.components.pipeline.AbstractEventPipeline.setupPipeline(AbstractEventPipeline.java:151)

	at org.apache.cocoon.components.pipeline.CachingEventPipeline.setup(CachingEventPipeline.java:246)

	at org.apache.cocoon.components.pipeline.CachingEventPipeline.generateKey(CachingEventPipeline.java:108)

	at org.apache.cocoon.components.pipeline.CachingStreamPipeline.process(CachingStreamPipeline.java:279)

	at org.apache.cocoon.www.sitemap_xmap.wildcardMatchN18B(sitemap_xmap.java:1547)

	at org.apache.cocoon.www.sitemap_xmap.process(sitemap_xmap.java:1051)

	at org.apache.cocoon.www.sitemap_xmap.process(sitemap_xmap.java:997)

	at org.apache.cocoon.sitemap.Handler.process(Handler.java:160)

	at org.apache.cocoon.sitemap.Manager.invoke(Manager.java:103)

	at org.apache.cocoon.Cocoon.process(Cocoon.java:354)

	at org.apache.cocoon.servlet.CocoonServlet.service(CocoonServlet.java:488)

	at javax.servlet.http.HttpServlet.service(HttpServlet.java)

	at org.apache.tomcat.facade.ServletHandler.doService(ServletHandler.java:500)

	at org.apache.tomcat.core.Handler.service(Handler.java:223)

	at org.apache.tomcat.facade.ServletHandler.service(ServletHandler.java:448)

	at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:788)

	at org.apache.tomcat.core.ContextManager.service(ContextManager.java:701)

	at org.apache.tomcat.modules.server.Http10Interceptor.processConnection(Http10Interceptor.java:143)

	at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:424)

	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:497)

	at java.lang.Thread.run(Thread.java:484)