OK, this probably is supposed to be the easiest thing in the world, but I've been trying for the entire day, and it's still not working.. Any help is highly appreciated!

What I did:

1. Downloaded Tomcat 6.0.26 & Spring 3.0.1
2. Downloaded PetClinic from https://src.springframework.org/svn/spring-samples/petclinic
3. Built & deployed petclinic.war. Ran fine with default TopLink persistence.
4. Edited webapps/WEB-INF/spring/applicationContext-jpa.xml and changed jpaVendorAdaptor from TopLink to Hibernate.
5. Edited webapps/WEB-INF/web.xml and changed context-param from applicationContext-jdbc.xml to applicationContext-jpa.xml
6. Copied everything in the Spring 3.0.1 distribution to TOMCAT_HOME/lib.

7. Launched tomcat. Saw

   Caused by: java.lang.IllegalStateException: ClassLoader [org.apache.catalina.loader.WebappClassLoader] does NOT provide an 'addTransformer(ClassFileTransformer)' method. Specify a custom LoadTimeWeaver or start your Java virtual machine with Spring's agent: -javaagent:spring-agent.jar

8. Uncommented line <Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"/> in webapps/META-INF/context.xml.

9. Same error. Added that line to TOMCAT_HOME/context.xml

10. Deployed without error. However, when I do something it will issue an error saying

    java.lang.NoClassDefFoundError: javax/transaction/SystemException at org.hibernate.ejb.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:39) at org.hibernate.ejb.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:34) at org.springframework.orm.jpa.JpaTransactionManager.createEntityManagerForTransaction(JpaTransactionManager.java:400) at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:321) at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371) at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:336) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:102) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy34.findOwners(Unknown Source) at org.springframework.samples.petclinic.web.FindOwnersForm.processSubmit(FindOwnersForm.java:56) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:710) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:167) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:414) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:402) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:771) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552) at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:71) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.ClassNotFoundException: javax.transaction.SystemException at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1516) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1361) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 41 more

I feel silly.. What am I missing?