Vraptor httpsession invalidar

Assuntos Gerais
#1

Caros colegas, estou tentando invalidar a sessão do usuário utilizando a minha aplicação, porém recebo um erro:

public void invalidar(HttpSession session){
		session.invalidate();
}

O erro é o seguinte:

br.com.caelum.vraptor.InterceptionException: exception raised, check root cause for details: java.util.ConcurrentModificationException
br.com.caelum.vraptor.interceptor.ExecuteMethodInterceptor.intercept(ExecuteMethodInterceptor.java:86)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ExceptionHandlerInterceptor.intercept(ExceptionHandlerInterceptor.java:69)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:61)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ParametersInstantiatorInterceptor.intercept(ParametersInstantiatorInterceptor.java:90)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:59)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InstantiateInterceptor.intercept(InstantiateInterceptor.java:42)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InterceptorListPriorToExecutionExtractor.intercept(InterceptorListPriorToExecutionExtractor.java:44)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.FlashInterceptor.intercept(FlashInterceptor.java:81)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ResourceLookupInterceptor.intercept(ResourceLookupInterceptor.java:67)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.DefaultRequestExecution.execute(DefaultRequestExecution.java:70)
br.com.caelum.vraptor.VRaptor$1.insideRequest(VRaptor.java:92)
br.com.caelum.vraptor.ioc.spring.SpringProvider.provideForRequest(SpringProvider.java:56)
br.com.caelum.vraptor.VRaptor.doFilter(VRaptor.java:89)

root cause

java.util.ConcurrentModificationException
java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
java.util.AbstractList$Itr.next(AbstractList.java:343)
projeto.IndexController.invalidar(IndexController.java:69)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
br.com.caelum.vraptor.interceptor.ExecuteMethodInterceptor.intercept(ExecuteMethodInterceptor.java:57)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ExceptionHandlerInterceptor.intercept(ExceptionHandlerInterceptor.java:69)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:61)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ParametersInstantiatorInterceptor.intercept(ParametersInstantiatorInterceptor.java:90)
br.com.caelum.vraptor.core.LazyInterceptorHandler.execute(LazyInterceptorHandler.java:59)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InstantiateInterceptor.intercept(InstantiateInterceptor.java:42)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.InterceptorListPriorToExecutionExtractor.intercept(InterceptorListPriorToExecutionExtractor.java:44)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.FlashInterceptor.intercept(FlashInterceptor.java:81)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.interceptor.ResourceLookupInterceptor.intercept(ResourceLookupInterceptor.java:67)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:54)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.ToInstantiateInterceptorHandler.execute(ToInstantiateInterceptorHandler.java:56)
br.com.caelum.vraptor.core.DefaultInterceptorStack.next(DefaultInterceptorStack.java:53)
br.com.caelum.vraptor.core.DefaultRequestExecution.execute(DefaultRequestExecution.java:70)
br.com.caelum.vraptor.VRaptor$1.insideRequest(VRaptor.java:92)
br.com.caelum.vraptor.ioc.spring.SpringProvider.provideForRequest(SpringProvider.java:56)
br.com.caelum.vraptor.VRaptor.doFilter(VRaptor.java:89)

#2

Depois de muito tentar, resolvi o problema.
Vou deixar aqui a dica para quem tiver passando pelo mesmo problema.

public void invalidar(HttpSession session){
		session.setMaxInactiveInterval(0);
}

Coloquei o setMaxInactiveInterval ao invés do invalidate, pois assim não é necessário programar a remoção de atributos da sessão.
A lista de usuários online foi colocada em uma ArrayList do tipo HttpSession.

Quem quiser mais detalhes, só mandar pm.

#3