Implementing GuiceServlet - CreationException on Guice.createInjector()

[Kristian Vitsø]

I am already using Guice for regular DI in my application, and wants it to handle the servlets as well. The relevant classes are given below.The setup still works fine with my regular DI, but once I add a serving rule in GuiceServletModule, I get the attached error/stacktrace on startup (using Jetty).

I get the same message if I set it up as suggested on http://code.google.com/p/google-guice/wiki/Servlets as well. I cannot manage to find any useful information about this error. Is there anybody who understands why this fails?

Error on startup:

2012-05-16 15:46:31.535:WARN:oejw.WebAppContext:Failed startup of context o.m.j.p.JettyWebAppContext{...},file:...

com.google.inject.CreationException: Guice creation errors:<|<|1) Error in custom provider, java.lang.ClassCastException: com.google.inject.servlet.ServletDefinition cannot be cast to com.google.inject.Provider<|  at com.google.inject.servlet.ServletsModuleBuilder.configure(ServletsModuleBuilder.java:56)<|  while locating com.google.inject.servlet.ServletDefinition annotated with @com.google.inject.internal.UniqueAnnotations$Internal(value=1)<|  at com.google.inject.servlet.ManagedServletPipeline.<init>(ManagedServletPipeline.java:52)<|  while locating com.google.inject.servlet.ManagedServletPipeline<|    for parameter 1 at com.google.inject.servlet.ManagedFilterPipeline.<init>(ManagedFilterPipeline.java:62)<|  while locating com.google.inject.servlet.ManagedFilterPipeline<|  while locating com.google.inject.servlet.FilterPipeline<|    for parameter 0 at com.google.inject.servlet.GuiceFilter.setPipeline(GuiceFilter.java:86)<|<|1 error

at com.google.inject.internal.Errors.throwCreationExceptionIfErrorsExist(Errors.java:354)

at com.google.inject.InjectorBuilder.injectDynamically(InjectorBuilder.java:173)

at com.google.inject.InjectorBuilder.build(InjectorBuilder.java:113)

at com.google.inject.Guice.createInjector(Guice.java:92)

at com.google.inject.Guice.createInjector(Guice.java:69)

at com.google.inject.Guice.createInjector(Guice.java:59)

at no.wis.collecting.core.StatInitializer.contextInitialized(StatInitializer.java:45)

at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:764)

at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:406)

at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:756)

at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:242)

at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1221)

at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699)

at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:454)

at org.mortbay.jetty.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:256)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)

at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:167)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:90)

at org.eclipse.jetty.server.Server.doStart(Server.java:262)

at org.mortbay.jetty.plugin.JettyServer.doStart(JettyServer.java:65)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:511)

at org.mortbay.jetty.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:364)

at org.mortbay.jetty.plugin.JettyRunMojo.execute(JettyRunMojo.java:516)

at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)

at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)

at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)

at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)

at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)

at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)

at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)

at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)

at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)

at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)

at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)

at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)

at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)

Caused by: 

java.lang.ClassCastException: com.google.inject.servlet.ServletDefinition cannot be cast to com.google.inject.Provider

at com.google.inject.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:48)

at com.google.inject.InjectorImpl$4$1.call(InjectorImpl.java:758)

at com.google.inject.InjectorImpl.callInContext(InjectorImpl.java:811)

at com.google.inject.InjectorImpl$4.get(InjectorImpl.java:754)

at com.google.inject.servlet.ManagedServletPipeline.collectServletDefinitions(ManagedServletPipeline.java:70)

at com.google.inject.servlet.ManagedServletPipeline.<init>(ManagedServletPipeline.java:53)

at com.google.inject.servlet.ManagedServletPipeline$$FastClassByGuice$$c910e7a6.newInstance(<generated>)

at com.google.inject.internal.cglib.reflect.FastConstructor.newInstance(FastConstructor.java:40)

at com.google.inject.DefaultConstructionProxyFactory$1.newInstance(DefaultConstructionProxyFactory.java:60)

at com.google.inject.ConstructorInjector.construct(ConstructorInjector.java:85)

at com.google.inject.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:111)

at com.google.inject.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:45)

at com.google.inject.InjectorImpl.callInContext(InjectorImpl.java:811)

at com.google.inject.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:42)

at com.google.inject.Scopes$1$1.get(Scopes.java:54)

at com.google.inject.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:48)

at com.google.inject.SingleParameterInjector.inject(SingleParameterInjector.java:42)

at com.google.inject.SingleParameterInjector.getAll(SingleParameterInjector.java:66)

at com.google.inject.ConstructorInjector.construct(ConstructorInjector.java:84)

at com.google.inject.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:111)

at com.google.inject.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:45)

at com.google.inject.InjectorImpl.callInContext(InjectorImpl.java:811)

at com.google.inject.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:42)

at com.google.inject.Scopes$1$1.get(Scopes.java:54)

at com.google.inject.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:48)

at com.google.inject.FactoryProxy.get(FactoryProxy.java:56)

at com.google.inject.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:45)

at com.google.inject.InjectorImpl.callInContext(InjectorImpl.java:811)

at com.google.inject.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:42)

at com.google.inject.Scopes$1$1.get(Scopes.java:54)

at com.google.inject.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:48)

at com.google.inject.SingleParameterInjector.inject(SingleParameterInjector.java:42)

at com.google.inject.SingleParameterInjector.getAll(SingleParameterInjector.java:66)

at com.google.inject.SingleMethodInjector.inject(SingleMethodInjector.java:84)

at com.google.inject.InjectionRequestProcessor$StaticInjection$1.call(InjectionRequestProcessor.java:109)

at com.google.inject.InjectionRequestProcessor$StaticInjection$1.call(InjectionRequestProcessor.java:106)

at com.google.inject.InjectorImpl.callInContext(InjectorImpl.java:804)

at com.google.inject.InjectionRequestProcessor$StaticInjection.injectMembers(InjectionRequestProcessor.java:106)

at com.google.inject.InjectionRequestProcessor.injectMembers(InjectionRequestProcessor.java:74)

at com.google.inject.InjectorBuilder.injectDynamically(InjectorBuilder.java:168)

at com.google.inject.InjectorBuilder.build(InjectorBuilder.java:113)

at com.google.inject.Guice.createInjector(Guice.java:92)

at com.google.inject.Guice.createInjector(Guice.java:69)

at com.google.inject.Guice.createInjector(Guice.java:59)

at com.example.AppInitializer.contextInitialized(AppInitializer.java:45)

at org.eclipse.jetty.server.handler.ContextHandler.callContextInitialized(ContextHandler.java:764)

at org.eclipse.jetty.servlet.ServletContextHandler.callContextInitialized(ServletContextHandler.java:406)

at org.eclipse.jetty.server.handler.ContextHandler.startContext(ContextHandler.java:756)

at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:242)

at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1221)

at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699)

at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:454)

at org.mortbay.jetty.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:256)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)

at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:167)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:90)

at org.eclipse.jetty.server.Server.doStart(Server.java:262)

at org.mortbay.jetty.plugin.JettyServer.doStart(JettyServer.java:65)

at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)

at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:511)

at org.mortbay.jetty.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:364)

at org.mortbay.jetty.plugin.JettyRunMojo.execute(JettyRunMojo.java:516)

at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)

at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)

at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)

at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)

at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)

at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)

at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)

at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)

at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)

at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)

at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)

at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)

at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)

at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)

My web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

version="2.5">

<filter>

<filter-name>guiceFilter</filter-name>

<filter-class>com.google.inject.servlet.GuiceFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>guiceFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>  

<listener>

<listener-class>com.example.AppInitializer</listener-class>

</listener>

</web-app>

AppInitializer.java:

public class AppInitializer implements ServletContextListener {

    public void contextInitialized(ServletContextEvent sce) {

        

// ... 

        GuiceMainModule guiceMain = new GuiceMainModule();

        GuiceServletModule guiceServlet = new GuiceServletModule();

        Injector injector = Guice.createInjector(guiceMain, guiceServlet);

        App..setInjector(injector);

             

    }

}

GuiceServletModule.java

public class GuiceServletModule extends ServletModule {

    @Override

    protected void configureServlets() {

        serve("/hello").with(HelloWorld.class);

    }

}

HelloWorld.java

@Singleton

public class HelloWorld extends HttpServlet {

    private static final long serialVersionUID = 1L;

    // ...

    @Override

    protected void doGet(HttpServletRequest request,

                         HttpServletResponse response)

            throws ServletException, IOException {

        

        response.getWriter().print("<h1>Hello World!</h1>");

    }

}

[jordi]

did you tried to extend directly GuiceServletContextListener instead of implementing your own?

Here's the example: http://code.google.com/p/google-guice/wiki/ServletModule

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[Kristian Vitsø]

Yes, i tried an implementation identical to the example as well - with the same result: the error only occurs when binding a servlet in the code. If I don't, then it works fine (but nor servlets are served obviously). The reason I did not go with the suggested implementation (from the example) is that I already have my injector set up (the GuiceMainModule) and accessible through the App object. But this should be an ok solution, right (separate regular DI bindings and servlet bindings in 2 different module implementations and build one injector from those two)?

[Alen Vrečko]

Caused by:
java.lang.ClassCastException:
com.google.inject.servlet.ServletDefinition
cannot be cast to com.google.inject.Provider

ServletDefinition extends ProviderWithExtensionVisitor that extends
Provider. So this should not produce a ClassCastException.

You are doing something fishy with your jars and/or classloaders.
Check and recheck your setup.

For the second question. I find child injectors rather nice in this
cases.

@Override
protected Injector getInjector() {
return App.INJECTOR.createChildInjector(new ServerStuffModules());
}

Cheers
Alen