I'm having some issue running my GWT/Errai app in GAE (Google App Engine). Also not sure why my app cannot initialize ErraiProvider?

Error:

Uncaught exception from servlet

java.lang.NoClassDefFoundError: Could not initialize class org.jboss.errai.jaxrs.ErraiProvider

  at com.google.appengine.runtime.Request.process-c75f0be3ef583674(Request.java)

  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

  at java.lang.reflect.Constructor.newInstance(Constructor.java:33)

  at org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:132)

  at org.jboss.resteasy.spi.ResteasyProviderFactory.createProviderInstance(ResteasyProviderFactory.java:1801)

  at org.jboss.resteasy.spi.ResteasyProviderFactory.addMessageBodyReader(ResteasyProviderFactory.java:681)

  at org.jboss.resteasy.spi.ResteasyProviderFactory.registerProvider(ResteasyProviderFactory.java:1128)

  at org.jboss.resteasy.spi.ResteasyProviderFactory.registerProvider(ResteasyProviderFactory.java:1085)

  at org.jboss.resteasy.spi.ResteasyProviderFactory.registerProvider(ResteasyProviderFactory.java:1029)

  at org.jboss.resteasy.spi.ResteasyDeployment.registerProvider(ResteasyDeployment.java:508)

  at org.jboss.resteasy.spi.ResteasyDeployment.registration(ResteasyDeployment.java:316)

  at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:226)

  at org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap.contextInitialized(ResteasyBootstrap.java:28)

  at org.jboss.resteasy.plugins.guice.GuiceResteasyBootstrapServletContextListener.contextInitialized(GuiceResteasyBootstrapServletContextListener.java:22)

  at com.myapp.server.guice.CustomGuiceResteasyBootstrapServletContextListener.contextInitialized(CustomGuiceResteasyBootstrapServletContextListener.java:48)

  at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:548)

  at org.mortbay.jetty.servlet.Context.startContext(Context.java:136)

  at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)

  at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)

  at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)

  at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)

  at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:435)

  at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:442)

  at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:186)

  at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:306)

  at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:298)

  at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:439)

  at java.lang.Thread.run(Thread.java:722)

Code (Resteasy):

    @Override

    public void contextInitialized(ServletContextEvent servletContextEvent)  {

        ServletContext context = servletContextEvent.getServletContext();

        if (context != null) {

            if (context.getInitParameter("user-base-url") != null) {

                userBaseUrl = context.getInitParameter("user-base-url");

            }

            String override = System.getProperty("staticBaseUrl");

            if (override != null || context.getInitParameter("static-base-url") != null) {

                staticBaseUrl = (override != null) ? override : context.getInitParameter("static-base-url");

            }

        }

        super.contextInitialized(servletContextEvent); // <--- Line 48

    }

Update:

This is my application web XML config:

    <context-param>

        <param-name>resteasy.guice.modules</param-name>

        <param-value>com.myapp.server.guice.ServeModule</param-value>

    </context-param>

  <context-param>

  <param-name>resteasy.providers</param-name>

  <param-value>org.jboss.errai.jaxrs.ErraiProvider</param-value>

  </context-param>

    <listener>

  <listener-class>

  com.myapp.server.guice.CustomGuiceResteasyBootstrapServletContextListener

  </listener-class>

    </listener>

  <context-param> 

    <param-name>resteasy.servlet.mapping.prefix</param-name> 

    <param-value>/</param-value> 

  </context-param>

    <servlet>

        <servlet-name>Resteasy</servlet-name>

        <servlet-class>

            org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher

        </servlet-class>

    </servlet>

    <servlet-mapping>

        <servlet-name>Resteasy</servlet-name>

        <url-pattern>/*</url-pattern>

    </servlet-mapping>