Недавно появилась задача поднять веб-приложение на сервере jetty 6. Веб-приложение использует библиотеку hibernate 3.2.5. Копируем варник приложения в $JETTY-HOME/webapps, запускаем, смотрим, что получилось:

java.lang.ExceptionInInitializerError
at main_package.HibernateUtil.<clinit>(HibernateUtil.java:28)
at sessionHandling.UserSessionDAOImpl.getUserSessionById(UserSessionDAOImpl.java:51)
at sessionHandling.UserSessionFilter.doFilter(UserSessionFilter.java:92)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:440)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:926)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.<init>(I)V
        at net.sf.cglib.core.DebuggingClassWriter.<init>(DebuggingClassWriter.java:47)
        at net.sf.cglib.core.DefaultGeneratorStrategy.getClassWriter(DefaultGeneratorStrategy.java:30)
        at net.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:24)
        at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:216)
        at net.sf.cglib.core.KeyFactory$Generator.create(KeyFactory.java:144)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:116)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:108)
        at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:104)
        at net.sf.cglib.proxy.Enhancer.<clinit>(Enhancer.java:69)
        at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.getProxyFactory(CGLIBLazyInitializer.java:117)
        at org.hibernate.proxy.pojo.cglib.CGLIBProxyFactory.postInstantiate(CGLIBProxyFactory.java:43)
        at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactory(PojoEntityTuplizer.java:162)
        at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:135)
        at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:55)
        at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:56)
        at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:295)
        at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:434)
        at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:109)
        at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
        at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:226)
        at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1294)
        at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
        at main_package.HibernateUtil.<clinit>(HibernateUtil.java:24)
        at sessionHandling.UserSessionDAOImpl.getUserSessionById(UserSessionDAOImpl.java:51)
        at sessionHandling.UserSessionFilter.doFilter(UserSessionFilter.java:92)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
        at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
        at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
        at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
        at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
        at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:440)
        at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
        at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
        at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
        at org.mortbay.jetty.Server.handle(Server.java:326)
        at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
        at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:926)
        at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
        at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
        at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
        at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
        at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

Дело в том, что в моём Hinernate 3.2.5 использует библиотеку Asm версии, отличной от версии Asm, используемой самим jetty. Также в Hibernate входит библиотека cglib, использующая Asm. Чтобы решить проблему, нужно для приложения использовать библиотеку сglib-nodep.jar вместо cglib.jar.