Tomcat 6.0.24 Exception: javax.servlet.ServletException: Servlet execution threw an exception

I am using java RestEasy Framwork for my application. I have some exception when I am trying to make a requet in tomcat server. Full stackTrace is:

Sep 26, 2011 1:50:06 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet my-servlet threw exception
java.lang.VerifyError: Cannot inherit from final class
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2331)
    at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:976)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1451)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1329)
    at org.codehaus.jackson.jaxrs.MapperConfigurator.getDefaultMapper(MapperConfigurator.java:69)
    at org.codehaus.jackson.jaxrs.JacksonJsonProvider.locateMapper(JacksonJsonProvider.java:587)
    at org.codehaus.jackson.jaxrs.JacksonJsonProvider.readFrom(JacksonJsonProvider.java:404)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:105)
    at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.read(GZIPDecodingInterceptor.java:61)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:108)
    at org.jb开发者_JAVA技巧oss.resteasy.security.doseta.DigitalVerificationInterceptor.read(DigitalVerificationInterceptor.java:35)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:108)
    at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:168)
    at org.jboss.resteasy.core.MethodInjectorImpl.injectArguments(MethodInjectorImpl.java:114)
    at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:137)
    at org.jboss.resteasy.core.ResourceMethod.invokeOnTarget(ResourceMethod.java:255)
    at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:220)
    at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:209)
    at org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:519)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:496)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:119)
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:208)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50)
    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.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:662)

What could be the problem?

The exception says that your servlet/JSP extends some other class, and that class is marked as final. Anyway, if it is a servlet (and not a JSP) that should have been detected at compile time.

MAke sure the spring-expressions.jar exists in your tomcat libs directory... i had to copy it there (apart from copying it to my WEB-INF/libs) but doing the copy of that jar to my tomcat directory solved my similar problem