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http://issues.apache.org/bugzilla/show_bug.cgi?id=41011 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: [EMAIL PROTECTED] 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! -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
