Yasson on SpringBoot: IOException Stream Closed

[amihaiemil]

Hi guys,

In Spring Boot 2.2.5, one can choose their own json provider.

1. Exclude the default Jackson
2. Add the Yasson dependency in pom.xml (which also brings the JSON-B API + JSON-P)

<dependency>
    <groupId>org.eclipse</groupId>
    <artifactId>yasson</artifactId>
    <version>1.0.6</version>
    <scope>runtime</scope>
</dependency>

3. Specify in application.properties the following:
   spring.http.converters.preferred-json-mapper=jsonb

This setup seems to work like a charm, except the logs contain an error at each request:

2020-03-16 16:09:20.306 ERROR 1540 --- [io-8090-exec-10] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception

java.io.IOException: Stream closed
        at sun.nio.cs.StreamEncoder.ensureOpen(StreamEncoder.java:45) ~[na:1.8.0_202]
        at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:140) ~[na:1.8.0_202]
        at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:229) ~[na:1.8.0_202]
        at org.springframework.http.converter.json.AbstractJsonHttpMessageConverter.writeInternal(AbstractJsonHttpMessageConverter.java:130) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:104) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:287) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:226) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:124) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1639) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_202]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_202]
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.31.jar:9.0.31]
        at java.lang.Thread.run(Thread.java:748) [na:1.8.0_202]


2020-03-16 16:09:20.354 ERROR 1540 --- [io-8090-exec-10]
s.e.ErrorMvcAutoConfiguration$StaticView : Cannot render error page for request [/country] and exception [Stream closed] as the response has already been committed. As a result, the response may have the wrong status code.

Apparently more people are having the same issue. See here and here.

Any idea why this could happen? Do you think it's a bug in Yasson or in Spring Boot?
Since the error does not occur with Jackson, I assume it could also be a bug in Yasson.

[aguibert]

hi @amihaiemil , can you please include the full stack trace? That will give us an idea of the exception flow. What's currently shown has no yasson classes in the stack so I have no idea what close flow we are in

[amihaiemil]

@aguibert I updated the description with the full stacktrace. Thank you!

I have opened the same Issue in the spring-boot repo, maybe they can also help :)

[aguibert]

After the Spring message converter is done calling out do JSON-B to write to a java.io.Writer it then calls flush(), but Yasson is closing the Writer after writing the JSON object.

I see two options here:
A) Spring boot could call writer.close() instead of writer.flush(). Close will first do a flush, but it will safely no-op if the writer is already closed
B) Yasson could not implicitly close the writer after calling toJson

I'm not finding any wording in the spec or javadoc that says an implementation should or should not close a Writer, but it would make more sense if the Writer was left open. I will try to make that change and see if it effects any existing test scenarios.

[amihaiemil]

@aguibert well, I think if Yasson doesn't close the Writer, that could be treated as a Memory Leak of sorts, or? I think Writers should be closed when whoever writes has finished writing.

[amihaiemil]

@aguibert Someone from Spring Boot answered. They are apparently convinced it's a bug in Yasson.

[aguibert]

I think it could go either way. Since the user is passing in the writer, they still hold a reference to the Writer and could close it on their own -- but this way is more error prone.

I ran a quick test and confirmed that yasson can not change behavior here. We have some basic scenarios that would break if we stopped closing the writer, for example:

        Writer writer = new StringWriter();
        bindingJsonb.toJson(new Long[]{5L}, writer);
        String writerValue = writer.toString();

Current behavior is that writerValue is [5] but if we don't close the writer then the user gets an empty string.

[wilkinsona]

FWIW, the user would get the expected string if Yasson called flush() rather than close() with the added benefit that they can then continue to use the writer if they wish to do so.

[amihaiemil]

@wilkinsona @aguibert Both Issues are closed now, yet this is clearly a bug. Andrew says Yasson cannot change behaviour. @wilkinsona maybe we can do something on Spring Boot's side,?

[aguibert]

that's a good compromise @wilkinsona, I'll re-open this issue