Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/621353#621353 -------------------------------------------------------------- Stepping into jboss-module code, I realized that the ServiceLoader.load method "overwritten" at runtime by the ConcurrentClassLoader.loadClass from jboss-modules, which at one point will read the jar file via the jarFileRessourceLoader method - BUT it will NOT look at the META-INF/services. At least I did not see that. So, the question would be: is this a feature or an issue or I am missing something ? Since I am new with AS7 would be nice if one could confirm. BR, Dan S. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/621353#621353] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/621470#621470 -------------------------------------------------------------- Here they are - I add services="import" based on : " https://docs.jboss.org/author/display/MODULES/Module+descriptors https://docs.jboss.org/author/display/MODULES/Module+descriptors" chapter services, imports and exports Same thing - I do not see the implementation class being read from the META-INF/services. The class that is loaded is only the interface class ! the module extension has the following definition: <?xml version="1.0" encoding="UTF-8"?> <module xmlns="urn:jboss:module:1.0" name="com.mycomp.module">     <resources>         <resource-root path="module-jboss-impl.jar"/>         <resource-root path="dnsjava.jar"/>         <resource-root path="module-api.jar"/>     </resources>     <dependencies>         <module name="javax.api"/>         <module name="org.javassist"/>         <module name="org.jboss.staxmapper"/>         <module name="org.jboss.as.controller"/>         <module name="org.jboss.as.server"/>         <module name="org.jboss.modules"/>         <module name="org.jboss.msc"/>         <module name="org.jboss.logging"/>         <module name="org.jboss.vfs"/>         <module name="org.apache.log4j"/>         <module name="javax.xml.bind.api"/>         <module name="javax.transaction.api"/>         <module name="com.sun.xml.bind"/>          <module name="com.mycomp.generic" services="import"/>     </dependencies> </module> the module that is "imported" into the module extension is: <?xml version="1.0" encoding="UTF-8"?> <module xmlns="urn:jboss:module:1.0" name="com.mycomp.generic">     <resources>         <resource-root path="generic-impl.jar"/>         <resource-root path="module-api.jar"/>     </resources>     <dependencies>         <module name="javax.api"/>         <module name="org.javassist"/>         <module name="org.jboss.staxmapper"/>         <module name="org.jboss.as.controller"/>         <module name="org.jboss.as.server"/>         <module name="org.jboss.modules"/>         <module name="org.jboss.msc"/>         <module name="org.jboss.logging"/>         <module name="org.jboss.vfs"/>         <module name="org.apache.log4j"/>         <module name="javax.xml.bind.api"/>         <module name="javax.transaction.api"/>         <module name="com.sun.xml.bind"/>     </dependencies> </module> -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/621470#621470] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/621544#621544 -------------------------------------------------------------- Hi,   Coming back on this && let's try to be more clear.   I added into module generic a jboss extension by implementing a dummy "org.jboss.as.controller.Extension" and I have another service "com.mycomp.havefun.NotReally" with it's implementation. META-INF/services update accordingly.   The module extension has already an implementation of "org.jboss.as.controller.Extension". META-INF/services updated. This same module has a definition into standalon.xml in order to be kickstarted by jboss modules at startup as an extension of AS7.   Now, with the previous module.xml I can see that BOTH jboss controller extensions from BOTH module are started.   BUT - I still fail to have that META-INF/service "com.mycomp.havefun.NotReally" loaded !   So, rephrasing my question, how can I have the jboss module kickstarting not only the jboss extension BUT my service too ?!? Don't see much on web.    I looked at the OSGI service and it seems that the OSGI framework that has some services defined is added programatically not as a module ...... And I am wondering if I have to do the same. If yes, any doc's on how to achieve that ?!? BR, Dan S. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/621544#621544] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Brian Stansberry [http://community.jboss.org/people/brian.stansberry] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/623583#623583 -------------------------------------------------------------- Another hook, besides mbeans, that the AS provides for installing services from a deployment is the MSC https://github.com/jbossas/jboss-msc/blob/master/src/main/java/org/jboss/... https://github.com/jbossas/jboss-msc/blob/master/src/main/java/org/jboss/.... Basically, the AS scans any deployment for a META-INF/services/org.jboss.msc.service.ServiceActivator file. If found, the ServiceLoader mechanism is used to load the specified ServiceActivator implementation, and then its activate() method is invoked. Via that mechanism you could install an MSC service, and that service could do your ServiceLoad start from its start() method, and also do any cleanup from its stop() method. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/623583#623583] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Brian Stansberry [http://community.jboss.org/people/brian.stansberry] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/623829#623829 -------------------------------------------------------------- Re: making an API / SPI available to other deployments... See https://docs.jboss.org/author/display/AS7/Class+Loading+in+AS7 https://docs.jboss.org/author/display/AS7/Class+Loading+in+AS7 for background and details on the following. A war, ear, or any other deployment can specify a dependency on external modules either by adding a jboss-deployment-structure.xml in its META-INF dir or by adding a Dependencies: manifest entry in MANIFEST.MF. See "Dependencies: Manifest Entries" and "JBoss Deployment Structure File" in the above doc. That module can either be one of the modules in the $JBOSS_HOME/modules dir, or it can be a module the AS dynamically creates when a deployment (e.g. a jar containing the API/SPI) is deployed. For modules dynamically created for deployments, the name of the module is "deployment.xxx". See "Deployment Module Names" in the above doc for details on "xxx". Simple example, if you had a jar "my-spi.jar" that included your SPI, you could deploy it, and then a war that needed visibility to the classes in that module could add this to its META-INF/MANIFEST.MF Dependencies: deployment.my-spi.jar -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/623829#623829] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/623873#623873 -------------------------------------------------------------- OK. I also tryed in a different way: setting in the "ee" subsystem the jar files as global modules and that seemed to work too. Thanks! BR, Dan S -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/623873#623873] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

David Lloyd [http://community.jboss.org/people/dmlloyd] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625522#625522 -------------------------------------------------------------- That's not really true.  Neither JBoss Modules nor JBoss AS will actively browse modules for services as this would be a significant performance drain to little advantage.  So services are never "discarded", they're simply ignored until someone asks for them. I see a couple items of confusion here.  First any module which provides an AS extension must be in the static module repository, because extensions are initialized during AS boot and there are no deployments at this early stage.  Second, the ServiceActivator interface (which is what I assume you're referring to as having a "service defined") is only read by deployment descriptors, so any ServiceActivators in a static modue will be ignored.  *However*, an extension module can define services through other APIs so this is not really a limitation. Okay here's another point of confusion.  The JBoss Modules service loader *is* the "regular" ServiceLoader, just wrapped up in a helper which provides the module's class loader for you.  This point of confusion seems to be masking the *real* problem.  If you want your extension module to "see" the service provided by its module dependency, you simply add 'services="import"' to the dependency element for that dependency.  If you want other modules which import the extension module to "see" the services provided by that dependency, then instead use 'services="export"'.  That's it; this will make it work whether you're using Module.loadService() or ServiceLoader. As I have said, the two are one and the same. This is only done when the service is explicitly declared like above.  If we did not filter these by default, then every module would see tons and tons of extra services which may or may not actually be desired and might actually be completely wrong.  However we *do* allow services to be shared across dependencies already as I've described, which neatly solves the problem. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625522#625522] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Brian Stansberry [http://community.jboss.org/people/brian.stansberry] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625561#625561 -------------------------------------------------------------- Here's my guess at to what is going on. If this doesn't describe what you're doing, then never mind. ;) You have a class ModuleExtensionClass that's in your ModuleExtension module. And another class ServiceAPIClass that's either in ModuleExtension or Module. In ModuleExtensionClass.initialize(ExtensionContext) you are calling ServiceLoader.load(ServiceAPIClass.class) If that call is failing with a CNFE, it's a sign that the module dependencies aren't set up right. But my theory is that's not what's happening. If I'm correct so far, does using this call work? ServiceLoader.load(ServiceAPIClass.class, ModuleExtensionClass.class.getClassLoader()) The single arg variant of ServiceLoader.load is the same as calling ServiceLoader.load(Class c, Thread.currentThread().getContextClassLoader()); In AS 7.0.0/7.0.1 when Extension.initialize is called the TCCL is null, so you're not going to get the correct classloader. We have changed this in master, so in 7.0.2 when Extension.initialize is called, the TCCL will the defining classloader of the Extension impl (i.e. ModuleExtensionClass.class.getClassLoader()). So, if my theory is right you should find this works in a current build of master but not in 7.0.1. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625561#625561] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625574#625574 -------------------------------------------------------------- The point is the following, the java.util.ServiceLoader is the common used and portable way of accessing services accross any java platform ! We do aggree on that I hope ! Thus, my point is the following one: if I want to have a ModuleExtension that needs to implement a service then I do not have any issue that I  need to use the ServiceLoader from jboss modules ! That I understand very well, it is a jboss-module way of doing things. The issue to me is that if the ModuleExtension needs a service from another package that was never intended to be an extention, thus a Module only, then when I want to  access a service from that Module I should NOT need to use the jboss-module ServiceLoader API ! I should be able to use the java.util.ServiceLoader as does any WAR/RAR or other type of app deployed as long as the dependency is set properly! My point is that in 7.0.0 that does NOT work ! Unless I am doing stupind things around - which is always a possibility - but I doubt since I am not the only one in my team to have the same experience ! I used all kind of setups, including the service="import" if I am not wrong ! And I think, from a design point of view, what I want to do should be correct and supported ! So, since so far I used 7.0.0 give me some time to use 7.0.1. ServiceLoader.load(ServiceAPIClass.class) - fails; module.loadService(ServiceAPIClass.class) - works where module is the Module object based on the identifier. No matter the dependecy. I also tryed between others : ServiceLoader.load(ServiceAPIClass.class, TCCLSingletonService.class.getClassLoader().getParent()) - fails I'll try what you mentioned. Give me some time. I'll try to attach the eclipse projects next time with all setup if I can. BR, Dan S.  -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625574#625574] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

David Lloyd [http://community.jboss.org/people/dmlloyd] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625587#625587 -------------------------------------------------------------- I just want to make it clear that you do NOT need to use the jboss modules service loader API.  This has never been required, nor will it ever be required.  This API exists as a convenience only. As Brian said, you should always be using the two-argument form of java.util.ServiceLoader#load() and provide your own class loader with it (I don't know what you're trying to accomplish with the getParent() but it's a safe bet that it's not the right thing to do).  Usually this is just "getClass().getClassLoader()", though you'll have to use a class literal in the static method case.  Relying on the thread context class loader is never a good idea under any circumstances.  If you rely on TCCL by using the one-argument form, you're setting yourself up for failure at +some+ point, either here and now or in the future.  If you use the two-argument form, your program will +always+ work as long as your class loader has the proper dependencies. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625587#625587] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Jason Greene [http://community.jboss.org/people/jason.greene] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625594#625594 -------------------------------------------------------------- To apply some more color, we have introduced a TCCL contract (What Brian was reffering to) in upstream master (which will be released in 7.0.2). This will make it much easier to deal with as you mention legacy code, and also JDK APIs which just were not designed for a modular world. As of 7.0.2: * The TCCL during any MSC Service will be the defining classloader * The TCCL during any management operation (includes extensions) will be the defining CL So in a nutshell single arg ServiceLoader will work in 7.0.2. Although maybe you want to try our local master before that? -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625594#625594] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Jason Greene [http://community.jboss.org/people/jason.greene] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625597#625597 -------------------------------------------------------------- FYI we have a latest binary build you can always grab here: http://hudson.jboss.org/jenkins/view/JBoss%20AS/job/JBoss-AS-7.0.x/lastSu... http://hudson.jboss.org/jenkins/view/JBoss%20AS/job/JBoss-AS-7.0.x/lastSu... -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625597#625597] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625608#625608 -------------------------------------------------------------- To Jason: many thanks for the link - that spares me for extra trouble :) To Brian: yes - there are for sure other people that are in the 'dark' as me and any open discussion is always productive. (+) I'll go ahead with Jason link and since I will be 'mean'  ;) - I will create one ModuleExtension and three Modules #1, #2, #3 with the following setup:      ModuleExtension loads --> ServiceLoadApiFromModule#1 --> executes the impl from Module#1      ServiceLoadApiFromModule#1 impl loads --> ServiceLoadApiFromModule#2 --> executes the impl from Module #2 see next (so Module#1 needs to have TCCL visibility on Module#2 )      ServiceLoadApiFromModule#2 --> ServiceLoadApiFromModule#3 (so Module#2 needs to have TCCL visibility on Module#3) --> executes the impl from Module #3 --> test stops      In a genric way, once in a Module, the Module should have visibility on all other Modules that were added as dependecies in the ModuleExtension, to cover more complex stuff. ModuleExtension -> ServiceLoadApiFromModule#1 loader can happen with 2 arguments since it comes from ModuleExtension (it can use even the jboss-module service loader) but the remaining: ServiceLoadApiFromModule#2,#3 - shall happen only with 1 argument since it is comming from Module and shall use the java.util.ServiceLoader.load(). Should the below achievable via module.xml setup as discussed ? If not, what would be the a code snapshot on classpath settings. Is this sound correct to you ?  BR, Dan S. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625608#625608] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625780#625780 -------------------------------------------------------------- Sorry Brian, but it does not look to me that is working. I did not go too far: ME-->M1 does not work so .... ME: module.xml has dependencies:       <module name="com.module.first"/>        M1       <module name="com.module.second"/>   M2       <module name="com.module.third"/>       M3 Then in the TCCL class: **import com.module.first.services.TestServicesIfc; ** **import com.module.first.services.TestServicesImpl; ** ..... module = Module.+getCallerModuleLoader+().loadModule(myModule.getIdentifier()); ServiceLoader<?> serviceLoader = module.loadService(TestServicesIfc. **class**);                      <--- SUCCESS since it is using the jboss-modules api Iterator<?> serviceIter = serviceLoader.iterator(); *if (serviceIter.hasNext()) { +log.info("TestServicesIfc -------> Found services class"); ...... ServiceLoader<TestServicesIfc> myService = ServiceLoader.+load+(TestServicesIfc.**class**);        <-- FAILSIterator<TestServicesIfc> iter = myService.iterator(); } **else** { ++log++.info("TestServicesIfc -------> NOT Second Found services class");} 10:44:57,216 INFO  [org.jboss.as.jmx.JMXConnectorService] (MSC service thread 1-2) Starting remote JMX connector 10:44:57,217 INFO  [org.jboss.as.remoting] (MSC service thread 1-3) Listening on /127.0.0.1:9999 10:44:59,268 INFO  [org.jboss.as.connector] (MSC service thread 1-3) Starting JCA Subsystem (JBoss IronJacamar 1.0.3.Fin al) 10:44:59,705 INFO  [org.jboss.as.connector.subsystems.datasources] (MSC service thread 1-2) Bound data source [java:jbos s/datasources/ExampleDS] 10:45:36,561 INFO  [com.modext.dans.services.TCCLSingletonService] (MSC service thread 1-4) TestServicesIfc -------> Fou nd services class 10:45:38,274 INFO  [com.module.first.services.TestServicesImpl] (MSC service thread 1-4) HELLO 10:45:50,258 INFO  [com.modext.dans.services.TCCLSingletonService] (MSC service thread 1-4) TestServicesIfc -------> NOT Second Found services class 10:45:55,941 INFO  [org.jboss.as.deployment] (MSC service thread 1-3) Started FileSystemDeploymentService for directory c:\jboss-as-7.1.0.Alpha1-SNAPSHOT\standalone\deployments 10:45:55,979 INFO  [org.jboss.as] (Controller Boot Thread) JBoss AS 7.1.0.Alpha1-SNAPSHOT "Lightning" started in 69825ms - Started 94 of 149 services (55 services are passive or on-demand) 10:45:58,719 INFO  [org.jboss.as.osgi] (MSC service thread 1-3) Stopping OSGi Framework 10:45:58,737 INFO  [org.jboss.as.logging] Restored bootstrap log handlers 10:45:58,792 INFO  [com.arjuna.ats.jbossatx] ARJUNA32018: Destroying TransactionManagerService 10:45:58,794 INFO  [com.arjuna.ats.jbossatx] ARJUNA32014: Stopping transaction recovery manager 10:45:58,799 INFO  [org.jboss.as] +*JBoss AS 7.1.0.Alpha1-SNAPSHOT*+ "Lightning" stopped in 96ms **if** (iter.hasNext()) { ++log++.info("TestServicesIfc -------> Second trial: Found services class"); +*  -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625780#625780] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

David Lloyd [http://community.jboss.org/people/dmlloyd] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625790#625790 -------------------------------------------------------------- You did not do it correctly.  To see services from a dependency, you must add "services="import"" or "service="export"".  Normally you just do the former, and have a dependency for every module that you need to see services for. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625790#625790] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Brian Stansberry [http://community.jboss.org/people/brian.stansberry] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/625799#625799 -------------------------------------------------------------- Sorry about that; I should have mentioned the services="import" or services="export" bit. Thanks, David. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/625799#625799] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Brian Stansberry [http://community.jboss.org/people/brian.stansberry] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/626295#626295 -------------------------------------------------------------- Yes, the singleton will be respected. Say you have com.foo.Singleton.class and it only exists in jar singleton.jar. So long as there is only one module Mx that includes singleton.jar in its <resources> element, there will only be one classloader that defines a class named com.foo.Singleton. Other modules that add a dependency on Mx only declare that they want to have access to whatever classes Mx exposes; they aren't declaring that they can be a defining classloader for the bits described in Mx's <resources> element. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/626295#626295] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]

Dan Sirbu [http://community.jboss.org/people/lmcdasi] created the discussion "Re: META-INF/services for module extensions - question/issue" To view the discussion, visit: http://community.jboss.org/message/626976#626976 -------------------------------------------------------------- Brian,    Unfortunately it looks like I have to come back: (a) When I do remote debugging on the TCCL Service load I start to have the following exception. I recall being able to debug that until I am getting this behaviour. If I disable the remote debugging the startup is ok. 16:22:50,138 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-10) MSC00001: Failed to start service jboss.as.test.singleton: org.jboss.msc.service.StartException in service jboss.as.test.singleton: Failed to start service         at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1780) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_26]         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_26]         at java.lang.Thread.run(Thread.java:662) [:1.6.0_26] Caused by: java.util.NoSuchElementException         at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:340) [:1.6.0_26]         at java.util.ServiceLoader$1.next(ServiceLoader.java:421) [:1.6.0_26]         at com.moduleext.jboss.extension.services.TCCLSingletonService.start(TCCLSingletonService.java:91)         at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1824) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1759) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         ... 3 more (b) Beside M1, I do have M2. Both implement the same interface for the ServiceLoader. The first kickstarts ok but the second fails with CastException tough I am sure I did not mess around with the class type definition. 16:28:42,273 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-15) MSC00001: Failed to start service jboss.as.modext.singleton: org.jboss.msc.service.StartException in service jboss.as.modext.singleton: Failed to start service         at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1780) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_26]         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_26]         at java.lang.Thread.run(Thread.java:662) [:1.6.0_26] Caused by: java.util.ServiceConfigurationError: com.test.jboss.module.ifc.TestModuleIfc: Provider com.test.jboss.test.impl.TestModuleTwoImpl could not be instantiated: java.lang.ClassCastException         at java.util.ServiceLoader.fail(ServiceLoader.java:207) [:1.6.0_26]         at java.util.ServiceLoader.access$100(ServiceLoader.java:164) [:1.6.0_26]         at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:353) [:1.6.0_26]         at java.util.ServiceLoader$1.next(ServiceLoader.java:421) [:1.6.0_26]         at com.ericsson.modext.jboss.extension.services.TCCLSingletonService.start(TCCLSingletonService.java:91)         at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1824) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1759) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]         ... 3 more Caused by: java.lang.ClassCastException         at java.lang.Class.cast(Class.java:2990) [:1.6.0_26]         at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:345) [:1.6.0_26]         ... 7 more The code snipet: List<MyModule> myList = this.getModules(); Iterator<MyModule> myIter = myList.iterator(); while(myIter.hasNext()) {        MyModule mmodule = myIter.next();        ModuleIdentifier moduleIdentifier = mmodule.getIdentifier();        log.info("TCCLSingletonService -- > starting module: " + moduleIdentifier.getName());        try {                   Module module = Module.getCallerModuleLoader().loadModule(moduleIdentifier);                   ServiceLoader<?> serviceLoader = module.loadService(TestModuleIfc.class);                   Iterator<?> serviceIter = serviceLoader.iterator();                   while(serviceIter.hasNext()) {                            ((TestModuleIfc) serviceIter.next()).start(context);                   }       } catch () {                   ...................       } } -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/626976#626976] Start a new discussion in JBoss AS7 Development at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]