creating servlet in CQ - cannot be cast to javax.servlet.Servlet , Failed getting the service for reference | Community
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A
Anonymous
October 16, 2015
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creating servlet in CQ - cannot be cast to javax.servlet.Servlet , Failed getting the service for reference

  • October 16, 2015
  • 14 replies
  • 6056 views
Hi all,
 

I tried the following sample program for creating servlet in CQ but getting below error in logs:

 
07.10.2013 11:27:19.156 *WARN* [OsgiInstallerImpl] org.apache.sling.servlets.resolver.internal.SlingServletResolver bindServlet: Failed getting the service for reference [javax.servlet.Servlet] java.lang.ClassCastException: com.adobe.training.core.MySafeMethodServlet cannot be cast to javax.servlet.Servlet
at org.apache.sling.servlets.resolver.internal.SlingServletResolver.createServlet(SlingServletResolver.java:974)
at org.apache.sling.servlets.resolver.internal.SlingServletResolver.bindServlet(SlingServletResolver.java:936)
 
Any reason why this is happening. Why its giving error like:
1)  Failed getting the service for reference 
2) cannot be cast to javax.servlet.Servlet
 
 
 
Below is the sample code.
-----------------------------------------------
 
package com.adobe.training.core;
import java.io.IOException;
 
 
import javax.servlet.ServletException;
import javax.servlet.Servlet;
 
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.sling.SlingServlet;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
 
@SlingServlet(paths = "/bin/company/repo" , methods = "GET")
public class MySafeMethodServlet extends SlingSafeMethodsServlet  
{
private static final long serialVersionUID = -3960692666512058118L;
 
@Override 
 
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException , IOException
{
response.setHeader("Content-Type","application/json");
response.getWriter().print("{\"coming\" : \"soon\"}");
}
}
 
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    Best answer by Ojjis

    Hi,
    have you tried to use the @Component annotation with it like this small example:

     

    @Component(immediate = true, metatype = true, name = "com.adobe.training.core.MySafeMethodServlet", label = "Safe Methd Servlet", description = " A small test servlet") @SlingServlet(methods = { "GET" }, paths = "/bin/company/repo", generateComponent = false) public class MySafeMethodServlet extends SlingSafeMethodsServlet { private static final Logger log = LoggerFactory.getLogger(MySafeMethodServlet.class); protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response){ log.info("DoGetting"); } protected void activate(ComponentContext ctx) { log.info("Activating"); } protected void deactivate(ComponentContext ctx) { log.info("Deactivating"); } }

    /Johan

    14 replies

    A
    Anonymous
    October 16, 2015

    Thanks both of you for quick reply. Let me try . Will let you know shortly how it goes

    Ojjis
    OjjisAccepted solution
    Level 7
    October 16, 2015

    Hi,
    have you tried to use the @Component annotation with it like this small example:

     

    @Component(immediate = true, metatype = true, name = "com.adobe.training.core.MySafeMethodServlet", label = "Safe Methd Servlet", description = " A small test servlet") @SlingServlet(methods = { "GET" }, paths = "/bin/company/repo", generateComponent = false) public class MySafeMethodServlet extends SlingSafeMethodsServlet { private static final Logger log = LoggerFactory.getLogger(MySafeMethodServlet.class); protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response){ log.info("DoGetting"); } protected void activate(ComponentContext ctx) { log.info("Activating"); } protected void deactivate(ComponentContext ctx) { log.info("Deactivating"); } }

    /Johan

    smacdonald2008
    smacdonald2008
    Level 10
    October 16, 2015
    Content backfill required
    A
    Anonymous
    October 16, 2015

    Hi ,

     

    I tried Ojjis code first and now though i am not getting any error in logs but when I tried to access the servelet using browser i am getting below error:

    07.10.2013 12:13:57.808 *INFO* [0:0:0:0:0:0:0:1 [1381162437795] GET /bin/company/repo HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Resource /bin/company/repo not found
    07.10.2013 12:13:58.154 *INFO* [0:0:0:0:0:0:0:1 [1381162438144] GET /bin/company/repo HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Resource /bin/company/repo not found

    For your reference below is the complete error.log

    07.10.2013 12:13:43.572 *INFO* [JcrInstaller.1] org.apache.sling.installer.provider.jcr.impl.JcrInstaller Registering resource with OSGi installer: [InstallableResource, priority=200, id=/apps/company/install/company-core-0.0.1-SNAPSHOT.jar]
    07.10.2013 12:13:43.589 *INFO* [OsgiInstallerImpl] com.adobe.training.company-core Service [com.adobe.training.core.MySafeMethodServlet,1144] ServiceEvent UNREGISTERING
    07.10.2013 12:13:43.589 *INFO* [OsgiInstallerImpl] com.adobe.training.core.MySafeMethodServlet Rohit service deactivated
    07.10.2013 12:13:43.624 *INFO* [OsgiInstallerImpl] org.apache.sling.audit.osgi.installer Updated bundle com.adobe.training.company-core [231] from resource TaskResource(url=jcrinstall:/apps/company/install/company-core-0.0.1-SNAPSHOT.jar, entity=bundle:com.adobe.training.company-core, state=INSTALL, attributes=[org.apache.sling.installer.api.tasks.ResourceTransformer=:50:16:, Bundle-SymbolicName=com.adobe.training.company-core, Bundle-Version=0.0.1.SNAPSHOT], digest=1381162423439)
    07.10.2013 12:13:43.624 *INFO* [FelixDispatchQueue] com.adobe.training.company-core BundleEvent STOPPED
    07.10.2013 12:13:43.624 *INFO* [FelixDispatchQueue] com.adobe.training.company-core BundleEvent UNRESOLVED
    07.10.2013 12:13:43.625 *INFO* [FelixDispatchQueue] com.adobe.training.company-core BundleEvent UPDATED
    07.10.2013 12:13:43.625 *INFO* [FelixDispatchQueue] org.apache.felix.framework FrameworkEvent PACKAGES REFRESHED
    07.10.2013 12:13:43.627 *INFO* [FelixDispatchQueue] org.apache.felix.framework FrameworkEvent PACKAGES REFRESHED
    07.10.2013 12:13:43.880 *INFO* [FelixDispatchQueue] com.adobe.training.company-core BundleEvent RESOLVED
    07.10.2013 12:13:43.890 *INFO* [OsgiInstallerImpl] com.adobe.training.core.MySafeMethodServlet Rohit service activated
    07.10.2013 12:13:43.893 *INFO* [OsgiInstallerImpl] com.adobe.training.company-core Service [com.adobe.training.core.MySafeMethodServlet,1145] ServiceEvent REGISTERED
    07.10.2013 12:13:43.893 *INFO* [OsgiInstallerImpl] org.apache.sling.installer.core.impl.tasks.BundleStartTask Bundle started (bundle ID=231) : com.adobe.training.company-core
    07.10.2013 12:13:43.893 *INFO* [FelixDispatchQueue] com.adobe.training.company-core BundleEvent STARTED
    07.10.2013 12:13:57.808 *INFO* [0:0:0:0:0:0:0:1 [1381162437795] GET /bin/company/repo HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Resource /bin/company/repo not found
    07.10.2013 12:13:58.154 *INFO* [0:0:0:0:0:0:0:1 [1381162438144] GET /bin/company/repo HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Resource /bin/company/repo not found

    A
    Anonymous
    October 16, 2015

    Hi all,

    Just for your info I am trying to access the servlet using below URL

    http://localhost:4502/bin/company/repo

    And below is the output I am getting:

     

    No resource found

    Cannot serve request to /bin/company/repo in /libs/sling/servlet/errorhandler/404.jsp

    Request Progress:

    0 (2013-10-07 12:20:41) TIMER_START{Request Processing} 0 (2013-10-07 12:20:41) COMMENT timer_end format is {<elapsed msec>,<timer name>} <optional message> 0 (2013-10-07 12:20:41) LOG Method=GET, PathInfo=/bin/company/repo 0 (2013-10-07 12:20:41) TIMER_START{ResourceResolution} 0 (2013-10-07 12:20:41) TIMER_END{0,ResourceResolution} URI=/bin/company/repo resolves to Resource=NonExistingResource, path=/bin/company/repo 0 (2013-10-07 12:20:41) LOG Resource Path Info: SlingRequestPathInfo: path='/bin/company/repo', selectorString='null', extension='null', suffix='null' 0 (2013-10-07 12:20:41) TIMER_START{ServletResolution} 0 (2013-10-07 12:20:41) TIMER_START{resolveServlet(NonExistingResource, path=/bin/company/repo)} 2 (2013-10-07 12:20:41) LOG {0}: no servlet found 2 (2013-10-07 12:20:41) TIMER_END{2,resolveServlet(NonExistingResource, path=/bin/company/repo)} Using servlet org.apache.sling.servlets.get.DefaultGetServlet 2 (2013-10-07 12:20:41) TIMER_END{2,ServletResolution} URI=/bin/company/repo handled by Servlet=org.apache.sling.servlets.get.DefaultGetServlet 2 (2013-10-07 12:20:41) LOG Applying Requestfilters 2 (2013-10-07 12:20:41) LOG Calling filter: org.apache.sling.bgservlets.impl.BackgroundServletStarterFilter 2 (2013-10-07 12:20:41) LOG Calling filter: org.apache.sling.rewriter.impl.RewriterFilter 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.core.impl.WCMRequestFilter 2 (2013-10-07 12:20:41) LOG Calling filter: org.apache.sling.i18n.impl.I18NFilter 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.theme.impl.ThemeResolverFilter 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.foundation.forms.impl.FormsHandlingServlet 2 (2013-10-07 12:20:41) LOG Calling filter: org.apache.sling.engine.impl.debug.RequestProgressTrackerLogFilter 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.mobile.core.impl.redirect.RedirectFilter 2 (2013-10-07 12:20:41) LOG RedirectFilter did not redirect (request extension does not match) 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.core.impl.warp.TimeWarpFilter 2 (2013-10-07 12:20:41) LOG Applying Componentfilters 2 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.core.impl.WCMComponentFilter 3 (2013-10-07 12:20:41) LOG Calling filter: com.day.cq.wcm.core.impl.WCMDebugFilter 3 (2013-10-07 12:20:41) TIMER_START{org.apache.sling.servlets.get.DefaultGetServlet#0} 3 (2013-10-07 12:20:41) TIMER_END{0,org.apache.sling.servlets.get.DefaultGetServlet#0} 3 (2013-10-07 12:20:41) LOG Applying Error filters 3 (2013-10-07 12:20:41) LOG Calling filter: org.apache.sling.rewriter.impl.RewriterFilter 3 (2013-10-07 12:20:41) TIMER_START{handleError:status=404} 3 (2013-10-07 12:20:41) TIMER_END{0,handleError:status=404} Using handler /libs/sling/servlet/errorhandler/404.jsp 3 (2013-10-07 12:20:41) LOG Found processor for post processing ProcessorConfiguration: {contentTypes=[text/html],order=-1, active=true, valid=true, processErrorResponse=true, pipeline=(generator=Config(type=htmlparser, config={}), transformers=(Config(type=linkchecker, config={}), Config(type=mobile, config=org.apache.sling.jcr.resource.JcrPropertyMap@400fad05), Config(type=mobiledebug, config=org.apache.sling.jcr.resource.JcrPropertyMap@4528441e), Config(type=contentsync, config=org.apache.sling.jcr.resource.JcrPropertyMap@5690310a), serializer=Config(type=htmlwriter, config={}))} 4 (2013-10-07 12:20:41) TIMER_END{4,Request Processing} Dumping SlingRequestProgressTracker Entries
    A
    Anonymous
    October 16, 2015

    Hi smacdonald2008

    Could you please share your complete code for Sling Servlet which you are mentioning. I will try the same now.

    Ojjis
    Ojjis
    Level 7
    October 16, 2015

    Thats quite strange, have tried it both in 5.6 and 5.5 with the exact code i wrote above and it works fine :S
    Is there anything indicating that there might be something wrong in the OSGi console about the servlet ?

    Now the logs clearly points out that the servlet handling your request is not your servlet but the default get servlet.
    This would lead to the error you get since there is actually no resource there. Is there any other things that you have added to your servlet ?
    Scotts great example works just in the same way except for the "post" method and you would probably benefit from looking at the stuff there as well.

    /Johan

    smacdonald2008
    smacdonald2008
    Level 10
    October 16, 2015

    The complete code is in the article that i referenced. All content is there and listed step by step - including how to build this with Maven. The Servlet is invoked using an AJAX request from a JSP.

     

    //Use JQuery AJAX request to post data to a Sling Servlet
     $.ajax({
             type: 'POST',    
             url:'/bin/mySearchServlet',
             data:'id='+ claimId+'&firstName='+ myFirst+'&lastName='+ myLast+'&address='+ address+'&cat='+ cat+'&state='+ state+'&details='+ details+'&date='+ date+'&city='+ city,
             success: function(msg){
               alert(msg); //display the data returned by the servlet
             }
         });

    A
    Anonymous
    October 16, 2015

    Hi Ojjis,

     

    Thanks for your reply. I donot think anything is missing. I started with the CQ Advance Training example. Not sure what could have been missing. I can see the servlet active in bundle , component , services. Also in logs there is no error when I deploy the servlet. Only when I try to access it via URL then I get NOT FOUND error...does this gives some clue.

    smacdonald2008
    smacdonald2008
    Level 10
    October 16, 2015

    Can you try and invoke the servlet (for testing purposes) from a JSP using an AJAX request (as shown in the community article) - lets make sure that it works. 

    Show more replies
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