Setting a default error page

evacchi commented 9 years ago

The default application behavior (at least to me) is to dump exceptions on the log, but nothing is shown on screen. e.g.:


2015-02-18 12:02:28.296 ERROR 83237 --- [nio-8080-exec-5] o.a.c.c.C.[Tomcat].[localhost]           : Exception Processing ErrorPage[errorCode=0, location=/error]

javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.NullPointerException
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:352)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:468)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:433)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:299)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:393)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)
Caused by: com.vaadin.server.ServiceException: java.lang.NullPointerException
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest(VaadinService.java:1466)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1420)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    ... 23 common frames omitted
Caused by: java.lang.NullPointerException: null
    at com.vaadin.server.LegacyCommunicationManager.getClientCache(LegacyCommunicationManager.java:194)
    at com.vaadin.server.LegacyCommunicationManager.repaintAll(LegacyCommunicationManager.java:421)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:76)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    ... 24 common frames omitted

I am not sure whether I am misconfiguring Spring or that is the expected behavior. How can I make Spring show the error in the browser?

thanks

peholmst commented 9 years ago

When are you experiencing this particular exception?

evacchi commented 9 years ago

basically whenever an exception is raised in the application itself. Here is a simple way to reproduce:

@VaadinUI
@Theme("valo")
public class Main extends UI {
    @Override
    protected void init(VaadinRequest request) {
        throw new Error("hello");
    }
}

result in the console (nothing is shown on the screen):

2015-02-19 10:07:59.423 ERROR 92466 --- [nio-8080-exec-5] com.vaadin.server.DefaultErrorHandler    : 

java.lang.Error: hello
    at org.tylproject.demos.fieldbinder.Main.init(Main.java:25)
    at com.vaadin.ui.UI.doInit(UI.java:641)
    at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:214)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)

2015-02-19 10:07:59.425 ERROR 92466 --- [nio-8080-exec-5] a.c.c.C.[.[.[.[springAwareVaadinServlet] : Servlet.service() for servlet [springAwareVaadinServlet] in context with path [] threw exception [com.vaadin.server.ServiceException: java.lang.Error: hello] with root cause

java.lang.Error: hello
    at org.tylproject.demos.fieldbinder.Main.init(Main.java:25)
    at com.vaadin.ui.UI.doInit(UI.java:641)
    at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:214)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)

2015-02-19 10:07:59.436 ERROR 92466 --- [nio-8080-exec-5] com.vaadin.server.DefaultErrorHandler    : 

java.lang.NullPointerException: null
    at com.vaadin.server.LegacyCommunicationManager.getClientCache(LegacyCommunicationManager.java:194)
    at com.vaadin.server.LegacyCommunicationManager.repaintAll(LegacyCommunicationManager.java:421)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:76)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:468)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:433)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:299)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:393)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)

2015-02-19 10:07:59.437 ERROR 92466 --- [nio-8080-exec-5] a.c.c.C.[.[.[.[springAwareVaadinServlet] : Servlet.service() for servlet springAwareVaadinServlet threw exception

java.lang.NullPointerException: null
    at com.vaadin.server.LegacyCommunicationManager.getClientCache(LegacyCommunicationManager.java:194)
    at com.vaadin.server.LegacyCommunicationManager.repaintAll(LegacyCommunicationManager.java:421)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:76)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:468)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:433)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:299)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:393)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)

2015-02-19 10:07:59.442 ERROR 92466 --- [nio-8080-exec-5] o.a.c.c.C.[Tomcat].[localhost]           : Exception Processing ErrorPage[errorCode=0, location=/error]

javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.NullPointerException
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:352)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:721)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:468)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:433)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:299)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:393)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:744)
Caused by: com.vaadin.server.ServiceException: java.lang.NullPointerException
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest(VaadinService.java:1466)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1420)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350)
    ... 23 common frames omitted
Caused by: java.lang.NullPointerException: null
    at com.vaadin.server.LegacyCommunicationManager.getClientCache(LegacyCommunicationManager.java:194)
    at com.vaadin.server.LegacyCommunicationManager.repaintAll(LegacyCommunicationManager.java:421)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:76)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408)
    ... 24 common frames

peholmst commented 9 years ago

OK, I'll have a look.

gjrtimmer commented 9 years ago

Thought: To me it looks like we have to find a smart way to link spring default /error handler into Vaadin. On an error spring tries to load / redirect the /error handler, and this is not handled by Vaadin.

evacchi commented 9 years ago

yup, that was my thought as well, there is probably a way to fallback on Spring's default. The thing is apparently Vaadin4Spring is conflicting with boot's default config

If no mapping from /error to a View can be found, Spring Boot defines its own fall-back error page - the so-called “Whitelabel Error Page” (a minimal page with just the HTTP status information and any error details, such as the message from an uncaught exception). If you rename the error.html template to, say, error2.html then restart, you will see it being used.

source: http://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc

gjrtimmer commented 9 years ago

I think we somehow need to integrate the spring /error with a UI's error handling, or capture and redirect.

In the sample created by markoradinovic there is a custom SpringErrorHandler which is set as the default error handler of a UI. This error handler is customized to capture and handle the AccessDeniedException of the spring-security module.

We may need something like this to capture all the exceptions from the spring framework and redirect them to be handled by a ErrorHandler which is configured within the UI.

Idea: Can we use AOP to maybe replace the default ErrorHandling of a UI, and then use AOP to capture the exceptions of the spring framework and redirect the exceptions to be handled within the UI ?

@evacchi @peholmst Any thought on this suggestion ?

@joshlong As a guru of the Spring framework / spring-security; can this be done ? Is there something within the spring framework which allows a full redirect / custom error handling, which bypasses or overrides the default /error handling ?

peholmst commented 9 years ago

Exceptions that are thrown when invoking beans from within the UI should already be handled by the UIs error handler. I assume this has to do with errors that occur outside of a UI?

evacchi commented 9 years ago

@peholmst nope, see my code above https://github.com/peholmst/vaadin4spring/issues/189#issuecomment-75021864

@GJRTimmer I think AOP is probably overkill. I'm not a Spring expert, but I guess there is a clean way to show the standard /error page. I feel like either Vaadin or Vaadin4Spring are inadvertedly hooking into the default somehow.

peholmst commented 9 years ago

@evacchi Do you run the application as a standalone Spring boot application or as a WAR? When I tried to run a standalone application that threw an exception in UI.init(), I got the standard Tomcat HTTP Status 500 page.

evacchi commented 9 years ago

that is really strange. I am getting it by running as standalone. May ask you to look at the demo app for the field-binder? https://github.com/tyl/field-binder if I throw an exception in there I get the error above. might have something to do with my config, but I really don't see how

EDIT: apparently the error originates in VaadinServlet.java

    public boolean synchronizedHandleRequest(VaadinSession session,
            VaadinRequest request, VaadinResponse response) throws IOException {
        try {
            assert UI.getCurrent() == null;

            // Update browser information from the request
            session.getBrowser().updateRequestDetails(request);

            UI uI = getBrowserDetailsUI(request, session);

            session.getCommunicationManager().repaintAll(uI);

            JsonObject params = Json.createObject();
            params.put(UIConstants.UI_ID_PARAMETER, uI.getUIId());
            String initialUIDL = getInitialUidl(request, uI);
            params.put("uidl", initialUIDL);

            return commitJsonResponse(request, response,
                    JsonUtil.stringify(params));
        } catch (JsonException e) {
            throw new IOException("Error producing initial UIDL", e);
        }
    }

this line:

            UI uI = getBrowserDetailsUI(request, session);

returns null

peholmst commented 9 years ago

I'll have a look.

peholmst commented 9 years ago

@evacchi I have the demo app up and running. Is there anything in particular I should try?

evacchi commented 9 years ago

just edit the file src/main/java/org/tylproject/demos/fieldbinder/Main.java so that it throws an exception. Just put a throw new Error() at the end of the init() method

peholmst commented 9 years ago

Reproduced. I see an empty screen.

evacchi commented 9 years ago

just in case: the demo on the 1.3-SNAPSHOT-gridsupport branch uses vaading4spring 0.0.5-SNAPSHOT

peholmst commented 9 years ago

OK, thanks

peholmst / vaadin4spring

Setting a default error page #189