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Posted to dev@tomcat.apache.org by bu...@apache.org on 2006/11/21 23:22:25 UTC
DO NOT REPLY [Bug 41011] New: - duplicate class definition error when JSPs loaded from multiple threads
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Summary: duplicate class definition error when JSPs loaded from
multiple threads
Product: Tomcat 5
Version: 5.5.17
Platform: PC
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P2
Component: Catalina
AssignedTo: tomcat-dev@jakarta.apache.org
ReportedBy: crv@itasoftware.com
After switching to a client configuration where two JSP pages are loaded
simultaneously, I started getting LinkageErrors 10-20% of the time after
restarting Tomcat. By passing -verbose:class to the JVM, I discovered that:
1. If the JSP classes and their dependencies are loaded one at a time,
everything is fine.
2. If the same classes are loaded concurrently in different threads, some of the
dependencies may be loaded twice. In this case the -verbose:class output shows
a class loaded twice from the same location.
This tends to happen to me with the Struts Tiles classes, which are used by both
JSPs. The first JSP starts loading its classes:
[Loaded org.apache.jsp.WEB_002dINF.include.xxx.pages.sidebar_jsp from
file:/xxx/catalina-base/work/Catalina/localhost/_/]
[Loaded org.apache.struts.taglib.tiles.PutTagParent from
file:/xxx/repository/struts/struts/1.2.9/struts-1.2.9.jar]
[Loaded org.apache.struts.taglib.tiles.PutListTagParent from
file:/xxx/repository/struts/struts/1.2.9/struts-1.2.9.jar]
...
The second JSP starts loading before the first finishes:
[Loaded org.apache.jsp.WEB_002dINF.include.xxx.pages.welcome_jsp from
file:/xxx/catalina-base/work/Catalina/localhost/_/]
[Loaded org.apache.struts.taglib.tiles.InsertTag$InsertHandler from
file:/xxx/repository/struts/struts/1.2.9/struts-1.2.9.jar]
One of the Tiles classes ends up being loaded twice:
[Loaded org.apache.struts.taglib.tiles.PutTag from
file:/xxx/repository/struts/struts/1.2.9/struts-1.2.9.jar]
[Loaded org.apache.struts.taglib.tiles.PutTag from
file:/xxx/repository/struts/struts/1.2.9/struts-1.2.9.jar]
The second JSP pages fails to render:
2006-11-21 11:32:49,617 [http-8080-Processor3] ERROR
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/].[jsp] -
Servlet.service() for servlet jsp threw exception
java.lang.LinkageError: duplicate class definition:
org/apache/struts/taglib/tiles/PutTag
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at
org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:880)
at
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1319)
at
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1198)
at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:127)
at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:65)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at
org.apache.jsp.WEB_002dINF.include.xxx.pages.welcome_jsp._jspx_meth_tiles_put_0(welcome_jsp.java:135)
at
org.apache.jsp.WEB_002dINF.include.xxx.pages.welcome_jsp._jspx_meth_tiles_insert_0(welcome_jsp.java:109)
at
org.apache.jsp.WEB_002dINF.include.xxx.pages.welcome_jsp._jspService(welcome_jsp.java:79)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
at
org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
at
org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
at
org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1085)
at
org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:263)
at
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:398)
at
org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:318)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:241)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at xxx.ResponseHeaderInserter.doFilter(ResponseHeaderInserter.java:62)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:541)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:613)
The error seems to be recoverable, ie. I can hit refresh and it works. I see
that there have been some WebappClassLoader synchronization issues in the past.
I've only tried 5.5.17, but I don't think recent fixes were related (maybe
revision 469360?).
I'm using a custom Loader (to load jars from outside of WEB-INF/lib), but it
just wraps a normal WebappLoader(getContainer().getParentClassLoader()) and
calls addRepository with file URLs. I don't think it's related to this situation...
Java version:
java version "1.5.0_08"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_08-b03)
Java HotSpot(TM) 64-Bit Server VM (build 1.5.0_08-b03, mixed mode)
Thanks!
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DO NOT REPLY [Bug 41011] - duplicate class definition error when JSPs loaded from multiple threads
Posted by bu...@apache.org.
DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG�
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://issues.apache.org/bugzilla/show_bug.cgi?id=41011>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND�
INSERTED IN THE BUG DATABASE.
http://issues.apache.org/bugzilla/show_bug.cgi?id=41011
------- Additional Comments From crv@itasoftware.com 2006-11-22 14:11 -------
Hmm, I'm having trouble reproducing today. I guess I'll need to investigate
further.
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DO NOT REPLY [Bug 41011] - duplicate class definition error when JSPs loaded from multiple threads
Posted by bu...@apache.org.
DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG�
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://issues.apache.org/bugzilla/show_bug.cgi?id=41011>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND�
INSERTED IN THE BUG DATABASE.
http://issues.apache.org/bugzilla/show_bug.cgi?id=41011
markt@apache.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |INVALID
------- Additional Comments From markt@apache.org 2006-12-09 21:32 -------
Looking at the stack trace, Tomcat's WebappClassLoader couldn't find the class
and delegated to the parent class loader. It is an instance of
java.net.URLClassLoader that is loading the class.
Given it is the JVM that is loading the class, this looks like a synchronisation
(or rather lack of synchronisation) issue with the JVM. A quick check of the JVM
source suggests this is likely since I can't see any synchronisation at all.
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DO NOT REPLY [Bug 41011] - duplicate class definition error when JSPs loaded from multiple threads
Posted by bu...@apache.org.
DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG�
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://issues.apache.org/bugzilla/show_bug.cgi?id=41011>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND�
INSERTED IN THE BUG DATABASE.
http://issues.apache.org/bugzilla/show_bug.cgi?id=41011
------- Additional Comments From chris@sourcelabs.com 2006-11-22 10:56 -------
Can you provide a stripped-down test case that reproduces this issue?
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