Spring component-scan broken in osgi container

Question

I'm trying to integrate spring DI into an existing jaxws project. I've got this working locally on tomcat but when I deploy to the remote container it doesn't appear to do the classpath scanning. I can see in the logs that on tomcat it registers my @Components as beans but on the remote server they're not mentioned at all.

What I do see is the stacktrace below. It looks like it's down to the quirky web container I have to use. It's the "integrated application server for IBM i". http://www-03.ibm.com/systems/i/software/ias/ I believe this is built on the eclipse architecture and when you install a war file it converts each app into a bundle. That's great but it's breaking my classpath scanning. :(

Does anyone have a solution for this? Thanks

673 [Thread-6] WARN  org.springframework.core.io.support.PathMatchingResourcePatternResolver  - Cannot search for matching files underneath URL [bundleresource://32/com/company/application/] because it does not correspond to a directory in the file system
java.io.FileNotFoundException: URL [bundleresource://32/com/company/application/] cannot be resolved to absolute file path because it does not reside in the file system: bundleresource://32/com/company/application/
    at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:205)
    at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:52)
    at org.springframework.core.io.UrlResource.getFile(UrlResource.java:169)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.doFindPathMatchingFileResources(PathMatchingResourcePatternResolver.java:526)
    at org.springframework.web.context.support.ServletContextResourcePatternResolver.doFindPathMatchingFileResources(ServletContextResourcePatternResolver.java:92)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.findPathMatchingResources(PathMatchingResourcePatternResolver.java:347)
    at org.springframework.core.io.support.PathMatchingResourcePatternResolver.getResources(PathMatchingResourcePatternResolver.java:266)
    at org.springframework.context.support.AbstractApplicationContext.getResources(AbstractApplicationContext.java:1269)
    at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.findCandidateComponents(ClassPathScanningCandidateComponentProvider.java:248)
    at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:242)
    at org.springframework.context.annotation.ComponentScanBeanDefinitionParser.parse(ComponentScanBeanDefinitionParser.java:84)
    at org.springframework.beans.factory.xml.NamespaceHandlerSupport.parse(NamespaceHandlerSupport.java:73)
    at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1438)
    at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1428)
    at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:185)
    at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.doRegisterBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:139)
    at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:108)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:493)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:390)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:334)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:174)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:209)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
    at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:125)
    at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:94)
    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:130)
    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:537)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:451)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at com.ibm.ws.webcontainer.webapp.WebApp.notifyServletContextCreated(WebApp.java:1678)
    at com.ibm.ws.webcontainer.webapp.WebApp.commonInitializationFinish(WebApp.java:371)
    at com.ibm.ws.webcontainer.webapp.WebApp.initialize(WebApp.java:347)
    at com.ibm.ws.webcontainer.webapp.WebGroup.addWebApplication(WebGroup.java:134)
    at com.ibm.ws.webcontainer.VirtualHost.addWebApplication(VirtualHost.java:145)
    at com.ibm.ws.webcontainer.WebContainer.addWebApp(WebContainer.java:542)
    at com.ibm.ws.webcontainer.WebContainer.addWebApplication(WebContainer.java:513)
    at com.ibm.pvc.internal.webcontainer.trackers.WebApplicationServiceTracker.addingService(WebApplicationServiceTracker.java:94)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackAdding(ServiceTracker.java:1064)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackInitialServices(ServiceTracker.java:926)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:330)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:274)
    at com.ibm.pvc.internal.webcontainer.trackers.XMLParserServiceTracker.initializeTrackers(XMLParserServiceTracker.java:520)
    at com.ibm.pvc.internal.webcontainer.trackers.XMLParserServiceTracker.startWebcontainer(XMLParserServiceTracker.java:235)
    at com.ibm.pvc.internal.webcontainer.trackers.XMLParserServiceTracker.addingService(XMLParserServiceTracker.java:140)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackAdding(ServiceTracker.java:1064)
    at org.osgi.util.tracker.ServiceTracker$Tracked.trackInitialServices(ServiceTracker.java:926)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:330)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:274)
    at com.ibm.pvc.internal.webcontainer.WebContainerActivator.start(WebContainerActivator.java:45)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:1009)
    at java.security.AccessController.doPrivileged(AccessController.java:251)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:1003)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:984)
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:350)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:279)
    at com.ibm.rcp.internal.util.BundleManager.start(BundleManager.java:74)
    at com.ibm.rcp.internal.util.BundleManager.start(BundleManager.java:179)
    at com.ibm.rcp.lifecycle.internal.application.BundleControlImpl.start(BundleControlImpl.java:125)
    at com.ibm.rcp.lifecycle.internal.application.BundleControlImpl.start(BundleControlImpl.java:106)
    at com.ibm.rcp.lifecycle.application.BundleControl.start(BundleControl.java:89)
    at com.ibm.lwi.application.LWIApplication.run(LWIApplication.java:149)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:600)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.callMethodWithException(EclipseAppContainer.java:574)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:195)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:386)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:600)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:561)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:501)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1239)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1215)
    at org.eclipse.core.launcher.Main.main(Main.java:30)
    at com.ibm.lwi.LaunchLWI$1.run(LaunchLWI.java:731)  

Looking at the code that throws the exception, it's checking if the protocol is file://.

if (!URL_PROTOCOL_FILE.equals(resourceUrl.getProtocol())) {
            throw new FileNotFoundException(
                    description + " cannot be resolved to absolute file path " +
                    "because it does not reside in the file system: " + resourceUrl);

I can see that the app has been exploded onto the filesystem. I wonder if there is a way to override this loader in spring to not care about the protocol and obviously still work? I don't care for the osgi features of the container. I just want my app to deploy.

The fallback seems to be abandon classpath scanning in favour of defining beans in xml but that;d be a real step back imo. :(

Answer 1

I hate the idea of answering my own question but it seemed the best way to report back what I did. I've upvoted the answers so far because they were helpful for me to make a decision.

Through reading the answers I've learned a bit about why classpath scanning is bad. Nonetheless it's a pretty common part of the spring framework these days. My solution was to go "old skool" and manually define my beans.

Can't do this:

<context:component-scan base-package="com.company.application.services" />

Do this instead:

<bean id="service1" class="com.company.application.services.impl.Service1" />
<bean id="service2" class="com.company.application.services.impl.Service2" />

You can at least still do this:

<context:annotation-config />

Annotation config means spring will still wire your beans together, it's just the process of discovering the beans that is being done manually. That's the compromise.

Ideally I would have preferred a means to deploy the project with component scanning but from what I can gather this requires changing the way the project is built specifically for an osgi container. My answer means it'll work both in an osgi and a normal container so it's less specialized.

If someone finds a way to deploy a war file with spring component scanning then I'll gladly re-consider the accepted answer.

Thanks

Answer 2

For your web application to run with spring you need spring dm, and therefore you need to have something like the following:

    <context-param>
    <param-name>contextClass</param-name>
    <param-value>org.springframework.osgi.web.context.support.OsgiBundleXmlWebApplicationContext</param-value>
</context-param>

Or for a complete sample take a look at the spring-osgi sample at pax-web: Sample web.xml