I have wrote following controller method:

    @RequestMapping(value = /member/createCompany/uploadImage1, method = RequestMethod.GET)

    @ResponseStatus(HttpStatus.OK)

    public Long handle() {

        return 1l;

    }

When I request this method in browser I see following:

HTTP Status 500 - Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]



type Exception report



message Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]



description The server encountered an internal error that prevented it from fulfilling this request.



exception



org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]

    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:948)

    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:620)

    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)

    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)

    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)

    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)

    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)

    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)

    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)

    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)

    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)

    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)

root cause



java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]

    org.springframework.util.Assert.notNull(Assert.java:112)

    org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:68)

    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)

    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)

    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)

    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)

    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)

    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)

    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)

    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:620)

    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)

    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(Charac

    .........

Did I implement server side wrong or is it client side problem?

Update to njjnex answer.

What should I do if I want to realize following logic inside controller method:

       if(someCondition){

           return 1l;

       }else{

         //I want to return 500 or 400 http code

       }