500 Servlet Exception

[show] java.lang.IllegalStateException: sendError() forbidden after buffer has
been committed.

java.lang.IllegalStateException: sendError() forbidden after buffer has
been committed.
	at com.caucho.server.http.HttpServletResponseImpl.sendError(HttpServletResponseImpl.java:631)
	at org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler.sendErrorResponse(DefaultDispatcherErrorHandler.java:80)
	at org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler.handleError(DefaultDispatcherErrorHandler.java:59)
	at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:920)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:587)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:89)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
	at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:89)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:156)
	at com.caucho.server.webapp.AccessLogFilterChain.doFilter(AccessLogFilterChain.java:95)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:289)
	at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:838)
	at com.caucho.network.listen.TcpSocketLink.dispatchRequest(TcpSocketLink.java:1345)
	at com.caucho.network.listen.TcpSocketLink.handleRequest(TcpSocketLink.java:1301)
	at com.caucho.network.listen.TcpSocketLink.handleRequestsImpl(TcpSocketLink.java:1285)
	at com.caucho.network.listen.TcpSocketLink.handleRequests(TcpSocketLink.java:1193)
	at com.caucho.network.listen.TcpSocketLink.handleAcceptTaskImpl(TcpSocketLink.java:992)
	at com.caucho.network.listen.ConnectionTask.runThread(ConnectionTask.java:117)
	at com.caucho.network.listen.ConnectionTask.run(ConnectionTask.java:93)
	at com.caucho.network.listen.SocketLinkThreadLauncher.handleTasks(SocketLinkThreadLauncher.java:169)
	at com.caucho.network.listen.TcpSocketAcceptThread.run(TcpSocketAcceptThread.java:61)
	at com.caucho.env.thread2.ResinThread2.runTasks(ResinThread2.java:173)
	at com.caucho.env.thread2.ResinThread2.run(ResinThread2.java:118)