Allow @WebListener ServletContextListeners to programmatically add servlets and filters #18303

janbartel · 2019-09-23T05:46:56Z

SpringBoot version 2.1.8.RELEASE

Please refer to jetty issue jetty/jetty.project#4103.
See also StackOverflow reports of same problem for Tomcat: https://stackoverflow.com/questions/44389716/spring-boot-embedded-tomcat-weblistener-scanned-by-servletcomponentscan

The issue is that a ServletContextListener that is annotated with @WebListener is not able to programmatically add Servlets (and I suppose Filters, but I didn't test that), but throws an UnsupportedOperationException. Here's an example of such an exception for jetty:

org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Jetty web server
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:156) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-5.1.9.RELEASE.jar!/:5.1.9.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at com.example.demo.DemoApplication.main(DemoApplication.java:13) ~[classes!/:0.0.1-SNAPSHOT]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) ~[demo-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) ~[demo-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:51) ~[demo-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
	at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:52) ~[demo-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Jetty web server
	at org.springframework.boot.web.embedded.jetty.JettyWebServer.initialize(JettyWebServer.java:114) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.web.embedded.jetty.JettyWebServer.<init>(JettyWebServer.java:86) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory.getJettyWebServer(JettyServletWebServerFactory.java:398) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory.getWebServer(JettyServletWebServerFactory.java:153) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]
	... 16 common frames omitted
Caused by: java.lang.UnsupportedOperationException: null
	at org.eclipse.jetty.servlet.ServletContextHandler$Context.checkDynamic(ServletContextHandler.java:1088) ~[jetty-servlet-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.servlet.ServletContextHandler$Context.addServlet(ServletContextHandler.java:1245) ~[jetty-servlet-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at com.example.demo.MyServletContextListener.contextInitialized(MyServletContextListener.java:16) ~[classes!/:0.0.1-SNAPSHOT]
	at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:930) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:555) ~[jetty-servlet-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:889) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:357) ~[jetty-servlet-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1443) ~[jetty-webapp-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1407) ~[jetty-webapp-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:822) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:276) ~[jetty-servlet-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:524) ~[jetty-webapp-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) ~[jetty-util-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:169) ~[jetty-util-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.server.Server.start(Server.java:407) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:110) ~[jetty-util-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:106) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.server.Server.doStart(Server.java:371) ~[jetty-server-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72) ~[jetty-util-9.4.21-SNAPSHOT.jar!/:9.4.21-SNAPSHOT]
	at org.springframework.boot.web.embedded.jetty.JettyWebServer.initialize(JettyWebServer.java:108) ~[spring-boot-2.1.8.RELEASE.jar!/:2.1.8.RELEASE]

This problem occurs because springboot is processing the @WebListener annotation and then using the ServletContext programmatic interfaces to add the listener: this classifies the listener as being programmatically added, and thus not permitted to add servlets/filters/listeners in its contextInitialized() method. See the ServletSpecification section 4.4:

If the ServletContext passed to the ServletContextListener’s
contextInitialized method where the ServletContextListener was neither
declared in web.xml or web-fragment.xml nor annotated with @WebListener
then an UnsupportedOperationException MUST be thrown for all the methods
defined in ServletContext for programmatic configuration of servlets, filters and
listeners.

Here is the springboot stacktrace showing where the @WebListener is being added as a programmatic listener:

	at org.eclipse.jetty.server.handler.ContextHandler.addProgrammaticListener(ContextHandler.java:718)
	at org.eclipse.jetty.servlet.ServletContextHandler.access$000(ServletContextHandler.java:89)
	at org.eclipse.jetty.servlet.ServletContextHandler$Context.addListener(ServletContextHandler.java:1439)
	at org.springframework.boot.web.servlet.ServletListenerRegistrationBean.register(ServletListenerRegistrationBean.java:116)
	at org.springframework.boot.web.servlet.RegistrationBean.onStartup(RegistrationBean.java:53)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.selfInitialize(ServletWebServerApplicationContext.java:228)
	at org.springframework.boot.web.embedded.jetty.ServletContextInitializerConfiguration.callInitializers(ServletContextInitializerConfiguration.java:65)
	at org.springframework.boot.web.embedded.jetty.ServletContextInitializerConfiguration.configure(ServletContextInitializerConfiguration.java:54)
	at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:498)
	at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1402)
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:822)
	at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:276)
	at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:524)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
	at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:169)
	at org.eclipse.jetty.server.Server.start(Server.java:407)
	at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:110)
	at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:106)
	at org.eclipse.jetty.server.Server.doStart(Server.java:371)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
	at org.springframework.boot.web.embedded.jetty.JettyWebServer.initialize(JettyWebServer.java:108)
	at org.springframework.boot.web.embedded.jetty.JettyWebServer.<init>(JettyWebServer.java:86)
	at org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory.getJettyWebServer(JettyServletWebServerFactory.java:398)
	at org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory.getWebServer(JettyServletWebServerFactory.java:153)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204)
	at com.example.demo.DemoApplication.main(DemoApplication.java:13)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:51)
	at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:52)

The text was updated successfully, but these errors were encountered:

wilkinsona · 2019-09-23T07:05:22Z

Thanks, @janbartel. This is a known limitation at the moment due to the way that Spring Boot scans for and registers @WebListener-annotated components. Is there an API in Jetty to register @WebListener-annotated components programmatically that would still allow them to perform their own programmatic registration of further components?

janbartel · 2019-09-23T07:19:38Z

@wilkinsona the way our own handling of @WebListener annotations adds a listener, using jetty-specific apis, is as follows:

ListenerHolder h = _context.getServletHandler().newListenerHolder(new Source(Source.Origin.ANNOTATION, clazz.getName()));
 h.setHeldClass(clazz);
_context.getServletHandler().addListener(h);

Where _context is a WebAppContext.

larsgrefer · 2019-10-05T22:35:45Z

For JoinFaces we've implemented a WebServerFactoryCustomizer which is able to add listeners to the embedded Jetty, Tomcat or Undertow in such a way that they aren't affected by the restrictions of Section 4.4 of the ServletSpec: https://github.com/joinfaces/joinfaces/blob/master/joinfaces-autoconfigure/src/main/java/org/joinfaces/autoconfigure/servlet/WebFragmentRegistrationBean.java

@wilkinsona Could the implementation behind @ServletComponentScan use this in order to remove this "known limitation"?

wilkinsona · 2020-07-31T11:00:14Z

I have a proposal for this but there is a small chance that it will be a breaking change. As such, I'm wonder if it may be a little too risky to do it in 2.2.x.

wilkinsona · 2020-08-03T13:19:49Z

The proposal requires some further thought as there are some package tangles at the moment.

wilkinsona · 2020-09-09T08:56:45Z

I've reworked the changes to remove the package tangles: https://github.com/wilkinsona/spring-boot/tree/gh-18303.

- Spring issues related to spring-projects/spring-boot#18303

janbartel mentioned this issue Sep 23, 2019

UnsupportedOperationException when adding servlet to ServletContext from @WebListener-annotated ServletContextListener jetty/jetty.project#4103

Closed

spring-projects-issues added the status: waiting-for-triage An issue we've not yet triaged label Sep 23, 2019

wilkinsona added the status: waiting-for-feedback We need additional information before we can continue label Sep 23, 2019

spring-projects-issues added status: feedback-provided Feedback has been provided and removed status: waiting-for-feedback We need additional information before we can continue labels Sep 23, 2019

larsgrefer mentioned this issue Oct 5, 2019

App startup error with omnifaces3-spring-boot-starter and ServletContextInitializer joinfaces/joinfaces#738

Open

wilkinsona changed the title ~~@WebListener ServletContextListeners should be able to programmatically add servlets and filters~~ @WebListener ServletContextListeners cannot programmatically add servlets and filters Jan 14, 2020

wilkinsona added type: bug A general bug and removed status: feedback-provided Feedback has been provided status: waiting-for-triage An issue we've not yet triaged labels Jan 14, 2020

wilkinsona added this to the 2.2.x milestone Jan 14, 2020

wilkinsona added the for: team-attention An issue we'd like other members of the team to review label Jul 31, 2020

wilkinsona self-assigned this Jul 31, 2020

philwebb modified the milestones: 2.2.x, 2.4.x Jul 31, 2020

philwebb added type: enhancement A general enhancement and removed for: team-attention An issue we'd like other members of the team to review type: bug A general bug labels Jul 31, 2020

wilkinsona changed the title ~~@WebListener ServletContextListeners cannot programmatically add servlets and filters~~ Allow @WebListener ServletContextListeners to programmatically add servlets and filters Jul 31, 2020

wilkinsona added the for: team-attention An issue we'd like other members of the team to review label Aug 3, 2020

philwebb removed the for: team-attention An issue we'd like other members of the team to review label Aug 5, 2020

wilkinsona added the for: team-attention An issue we'd like other members of the team to review label Sep 9, 2020

philwebb self-assigned this Sep 12, 2020

philwebb removed the for: team-attention An issue we'd like other members of the team to review label Sep 18, 2020

philwebb closed this as completed in fafc0a9 Oct 26, 2020

philwebb modified the milestones: 2.4.x, 2.4.0-RC1 Oct 27, 2020

philwebb mentioned this issue Jan 30, 2021

SpringBoot/Tomcat fails to start when a @WebListener has a constructor with an argument #25059

Closed

bencalegari added a commit to codeforamerica/shiba that referenced this issue Jan 30, 2021

Fix SessionListener to use @component

e1e917b

- Spring issues related to spring-projects/spring-boot#18303

bencalegari added a commit to codeforamerica/shiba that referenced this issue Jan 30, 2021

Fix SessionListener to use @component

03d7816

- Spring issues related to spring-projects/spring-boot#18303

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Allow @WebListener ServletContextListeners to programmatically add servlets and filters #18303

Allow @WebListener ServletContextListeners to programmatically add servlets and filters #18303

janbartel commented Sep 23, 2019

wilkinsona commented Sep 23, 2019

janbartel commented Sep 23, 2019

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wilkinsona commented Sep 9, 2020

Allow @WebListener ServletContextListeners to programmatically add servlets and filters #18303

Allow @WebListener ServletContextListeners to programmatically add servlets and filters #18303

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janbartel commented Sep 23, 2019

wilkinsona commented Sep 23, 2019

janbartel commented Sep 23, 2019

larsgrefer commented Oct 5, 2019

wilkinsona commented Jul 31, 2020

wilkinsona commented Aug 3, 2020

wilkinsona commented Sep 9, 2020