Hi community,
I have a strange problem with my Struts Action portlet: the portlet has a servlet that export certain data into Excel format (by org.apache.poi.hssf.usermodel.HSSFWorkbook class) and use a LocalServiceUtil class for load a list of object (i.e. Bollettino object).
The problem is that when load the list (BollettinoLocalServiceUtil.getBollettinos(-1, -1)) the method getBollettinos generate the exception:
The problem, by searching into forums and other resources, seems to be due to the existence of a duplicate library into classloader.
But this problem happens only when deploy portlet after restarting the server: if I use the servlet after firts start of JBoss(or after restart) the problem disappear and the XLS file is sucessfully created.
.
how can I fix this? Why LF duplicate library (how library? portal-service?) after portlet deploy?
The server installation seems to be ok and I never manually changed the libraries or their arrangement inside the server.
In the past I have created other portlet with same functionality (LF 5.2.3/Tomcat) without any problem.
Thank's in advance.
I have a strange problem with my Struts Action portlet: the portlet has a servlet that export certain data into Excel format (by org.apache.poi.hssf.usermodel.HSSFWorkbook class) and use a LocalServiceUtil class for load a list of object (i.e. Bollettino object).
The problem is that when load the list (BollettinoLocalServiceUtil.getBollettinos(-1, -1)) the method getBollettinos generate the exception:
java.lang.ClassCastException: it...BollettinoImpl cannot be cast to it....Bollettino
....
....
The problem, by searching into forums and other resources, seems to be due to the existence of a duplicate library into classloader.
But this problem happens only when deploy portlet after restarting the server: if I use the servlet after firts start of JBoss(or after restart) the problem disappear and the XLS file is sucessfully created.
.how can I fix this? Why LF duplicate library (how library? portal-service?) after portlet deploy?
The server installation seems to be ok and I never manually changed the libraries or their arrangement inside the server.
In the past I have created other portlet with same functionality (LF 5.2.3/Tomcat) without any problem.
Thank's in advance.
Gianluca Pindinelli:
But this problem happens only when deploy portlet after restarting the server: if I use the servlet after firts start of JBoss(or after restart) the problem disappear and the XLS file is sucessfully created.
So, to understand you correctly, you are saying that (1) the exceptions happen in the servlet, but no exceptions happen in the portlet even when the portlet calls the same services, and (2) there is no exception on first deployment, but errors come up when you redeploy the portlet a second or third time.
In that case, JBoss is probably caching the class loader for the servlet class, but does not do so for the portlet class. I suspect that the only way to resolve it would be to manually undeploy your plugin by deleting the folder, wait for JBoss to unregister it, and then redeploy your plugin.
If even that doesn't work, you will need to either use a different application server for development, or you will need to go through the tedious process of undeploying your plugin and restarting your JBoss instance every time you make a change.
Hi Minhchau,
thanks for your reply!
Yes..you have exactly described the problem. And I add that, at this point, the problem is certainly jboss because on Tomcat (in my previous projects) is all OK.
Unfortunately this does not work...always same exception
.
Unfortunately I can't use different AS and restart the server every time I deploy is a significant problem, because the system is on a production server.
Exists a way for disable the caching system of jboss AS for the servlet class or other possible solutions?
EDIT:
My portlet is a Struts Action portlet (org.apache.portals.bridges.struts.StrutsPortlet) and the problem seems to be like this:
http://www.liferay.com/community/forums/-/message_boards/message/4363758#_19_message_4363758... Jboss seems to have problem with classloader but I am not able to find how to solve the conflict..
I also noticed that the problem also appears with the filters (javax.portlet.filter.RenderFilter): I am forced to restart the server to see the changes made to the portlet filter...
Thanks in advance.
thanks for your reply!
So, to understand you correctly, you are saying that (1) the exceptions happen in the servlet, but no exceptions happen in the portlet even when the portlet calls the same services, and (2) there is no exception on first deployment, but errors come up when you redeploy the portlet a second or third time.
Yes..you have exactly described the problem. And I add that, at this point, the problem is certainly jboss because on Tomcat (in my previous projects) is all OK.
In that case, JBoss is probably caching the class loader for the servlet class, but does not do so for the portlet class. I suspect that the only way to resolve it would be to manually undeploy your plugin by deleting the folder, wait for JBoss to unregister it, and then redeploy your plugin.
Unfortunately this does not work...always same exception
.If even that doesn't work, you will need to either use a different application server for development, or you will need to go through the tedious process of undeploying your plugin and restarting your JBoss instance every time you make a change.
Unfortunately I can't use different AS and restart the server every time I deploy is a significant problem, because the system is on a production server.
Exists a way for disable the caching system of jboss AS for the servlet class or other possible solutions?
EDIT:
My portlet is a Struts Action portlet (org.apache.portals.bridges.struts.StrutsPortlet) and the problem seems to be like this:
http://www.liferay.com/community/forums/-/message_boards/message/4363758#_19_message_4363758... Jboss seems to have problem with classloader but I am not able to find how to solve the conflict..
I also noticed that the problem also appears with the filters (javax.portlet.filter.RenderFilter): I am forced to restart the server to see the changes made to the portlet filter...
Thanks in advance.
Hi all,
My problem has been fixed.
Here's the solution to my problem:
http://www.liferay.com/zh/community/wiki/-/wiki/Main/Using+Class+Loader+Proxy+classes+to+share+plugins+services
The idea is "If 2 or more custom portlets use same set of entity(e.g. access same set of DB table) generated from service builder, only 1 portlet-service.jar(auto generated in docroot\WEB-INF\lib\) should be deployed to server. Otherwise, "ClassCastException" would be raised."
I used method 2(II) from the article and works fine.
Based on its concept, I first create a new portlet project (common.war) to centralize all entities to be accessed by other portlets. Then put the built portlet-service.jar as a common jar to {server}\lib\ext. During development, other portlet (other.war) should also create a service.xml and modify the ServiceImpl as usual. Before deployment, make sure to delete portlet-service.jar in docroot\WEB-INF\lib of common.war and other.war.
Hope can help if someone reached his thread.
Or, any better alternatives for my case? Thanks
My problem has been fixed.
Here's the solution to my problem:
http://www.liferay.com/zh/community/wiki/-/wiki/Main/Using+Class+Loader+Proxy+classes+to+share+plugins+services
The idea is "If 2 or more custom portlets use same set of entity(e.g. access same set of DB table) generated from service builder, only 1 portlet-service.jar(auto generated in docroot\WEB-INF\lib\) should be deployed to server. Otherwise, "ClassCastException" would be raised."
I used method 2(II) from the article and works fine.
Based on its concept, I first create a new portlet project (common.war) to centralize all entities to be accessed by other portlets. Then put the built portlet-service.jar as a common jar to {server}\lib\ext. During development, other portlet (other.war) should also create a service.xml and modify the ServiceImpl as usual. Before deployment, make sure to delete portlet-service.jar in docroot\WEB-INF\lib of common.war and other.war.
Hope can help if someone reached his thread.
Or, any better alternatives for my case? Thanks
