Spring boot web application throws getOutputStream() has already been called for this response

Question

I have spring boot web application built using spring boot 1.4.0.RELEASE and embedded tomcat version is 8.5.4. I am seeing the "IllegalStateException due to getOoputStream() has already called" exception occasionally in my log. I don't know exactly when it comes.

The spring boot webapp built using jsp, tiles and mvc rest controller. The rest controller is very simple and it doesn't use responsestream. Here is my error log,

Caused by: java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.apache.catalina.connector.Response.getWriter(Response.java:609) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:211) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:109) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:109) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:118) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:111) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:176) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:120) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:75) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329) ~[tomcat-embed-jasper-8.5.4.jar!/:8.5.4]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:186) ~[spring-security-web-3.2.3.RELEASE.jar!/:3.2.3.RELEASE]
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) ~[spring-security-web-3.2.3.RELEASE.jar!/:3.2.3.RELEASE]
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:726) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:592) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:526) ~[tomcat-embed-core-8.5.4.jar!/:8.5.4]
    at org.apache.tiles.request.servlet.ServletRequest.doInclude(ServletRequest.java:243) ~[tiles-request-servlet-1.0.0.jar!/:1.0.0]
    at org.apache.tiles.request.servlet.ServletRequest.doForward(ServletRequest.java:226) ~[tiles-request-servlet-1.0.0.jar!/:1.0.0]
    at org.apache.tiles.request.AbstractClientRequest.dispatch(AbstractClientRequest.java:57) ~[tiles-request-api-1.0.0.jar!/:1.0.0]
    at org.apache.tiles.request.render.DispatchRenderer.render(DispatchRenderer.java:45) ~[tiles-request-api-1.0.0.jar!/:1.0.0]
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:259) ~[tiles-core-3.0.0.jar!/:3.0.0]
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:397) ~[tiles-core-3.0.0.jar!/:3.0.0]
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:238) ~[tiles-core-3.0.0.jar!/:3.0.0]
    at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:221) ~[tiles-core-3.0.0.jar!/:3.0.0]
    at org.apache.tiles.renderer.DefinitionRenderer.render(DefinitionRenderer.java:59) ~[tiles-core-3.0.0.jar!/:3.0.0]
    at org.springframework.web.servlet.view.tiles3.TilesView.renderMergedOutputModel(TilesView.java:132) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1257) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1037) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:980) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.2.RELEASE.jar!/:4.3.2.RELEASE]
    ... 25 more








   @Controller
    @RequestMapping("/")
    public class MainController{        
        @RequestMapping(value = {"/list"}, method = RequestMethod.GET)
        public String blacklist(ModelMap model) {
            //processing
            return "list";
        }

        @RequestMapping(value = {"/Find"}, method = RequestMethod.POST)
        public String find(ModelMap model, @ModelAttribute("attribute1")String attr) {
            //processing
            return "list";
        }
    }

Answer 1

if the bean/object you are returning, hasn't got the setters or getters, or can not be reflected, you will get this error.

Answer 2

If you use interceptor which works with it at the same time, please check it. Maybe interceptor use response - outputStream.

Answer 3

Mostly this error is related to calling any servlet method after response is committed. Check your servlet code to see if any line of code is written after response.forward or response.flush methods. It can be even System.out after response is written.