https://bz.apache.org/bugzilla/show_bug.cgi?id=57772
Bug ID: 57772
Summary: WebappClassLoader throws a ClassNotFoundError when the
Manager is deploying a new WAR
Product: Tomcat 8
Version: 8.0.20
Hardware: PC
OS: Linux
Status: NEW
Severity: critical
Priority: P2
Component: Manager
Assignee: [email protected]
Reporter: [email protected]
Overview:
When contexts are updated through the Tomcat manager interface,
ServletContextListener.contextDestroyed implementations which need to load
classes throw ClassNotFoundError.
Steps to reproduce:
1. Create an instance of Tomcat 8.0.20
2. In server.xml, configure the Host with unpackWARs="true" autoDeploy="false".
3. Check out the example webapp from
https://github.com/austinjones/ClassNotFoundGenerator
4. Build the testing WAR using the 'distribute' ant task.
5. Deploy the WAR using an HTTP request to this URL:
http://<your-local-tomcat>/manager/text/deploy?
war=path/to/workspace/ClassNotFoundGenerator/dist/ClassNotFoundGenerator.war
&config=path/to/workspace/ClassNotFoundGenerator/web/context.xml
&path=/ClassNotFoundGenerator
&update=true
6. Open localhost.log, and verify the ClassNotFoundError was logged.
Actual results:
The ClassNotFoundError is thrown by TestcaseContextListener.contextDestroyed,
and printed to localhost.log. Any further work the context listener was
responsible for is not executed.
Expected Results:
The WebappClassLoader successfully loads classes during
ServletContextListener.contextDestroyed, and completes without a throw. No
ClassNotFoundError is printed to localhost.log
Build Date & Hardware:
Tomcat 8.0.12 on CentOS Linux 6.6
Additional Builds and Platforms:
Tomcat 8.0.12 on Windows 7 SP1
Tomcat 8.0.20 on Windows 7 SP1
Tomcat 8.0.20 on CentOS Linux 6.6
Note: if you try the 'steps to reproduce' on 8.0.12, the deployment will
probably fail due to bug 56398 - which I worked around in 8.0.12. You'll be
able to deploy if you change the name of the test app to
'classnotfoundgenerator'.
Additional Information:
ServletContextListeners that need to load classes during the contextDestroyed
call throw ClassNotFoundError, when the application is deployed as a WAR
through the Manager interface. Here is an example listener, where
ThisClassNotFound is not loaded for the first time in contextDestroyed.
https://github.com/austinjones/ClassNotFoundGenerator/blob/master/src/com/avadyne/TestcaseContextListener.java
The stack trace of the ClassNotFoundError on 8.0.20 is:
6-Mar-2015 14:38:46.838 SEVERE [http-nio-8443-exec-5]
org.apache.catalina.core.StandardContext.listenerStop Exception sending context
destroyed event to listener instance of class
com.avadyne.TestcaseContextListener
java.lang.NoClassDefFoundError: com/avadyne/ThisClassNotFound
at
com.avadyne.TestcaseContextListener.contextDestroyed(TestcaseContextListener.java:27)
at
org.apache.catalina.core.StandardContext.listenerStop(StandardContext.java:4775)
at
org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5385)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
at
org.apache.catalina.core.StandardContext.reload(StandardContext.java:3739)
at org.apache.catalina.startup.HostConfig.reload(HostConfig.java:1304)
at
org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1236)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1491)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at
org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
at
com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at
org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1460)
at
org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:906)
at
org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:344)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:613)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
at
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
at
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
at
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
at
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: com.avadyne.ThisClassNotFound
at
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1305)
at
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1157)
... 45 more
The stack trace where Tomcat attempts to load ThisClassNotFound is (8.0.20):
Daemon Thread [http-nio-8443-exec-31] (Suspended)
owns: WebappClassLoader (id=3483)
owns: TestcaseContextListener (id=3488)
owns: StandardContext (id=3324)
owns: HostConfig (id=3323)
owns: SecureNioChannel (id=3313)
StandardRoot.getResourceInternal(String, boolean) line: 302
Cache.getResource(String, boolean) line: 65
StandardRoot.getResource(String, boolean, boolean) line: 216
StandardRoot.getClassLoaderResource(String) line: 225
WebappClassLoader(WebappClassLoaderBase).findResourceInternal(String,
String) line: 2548
WebappClassLoader(WebappClassLoaderBase).findClassInternal(String) line:
2405
WebappClassLoader(WebappClassLoaderBase).findClass(String) line: 854
WebappClassLoader(WebappClassLoaderBase).loadClass(String, boolean) line:
1274
WebappClassLoader(WebappClassLoaderBase).loadClass(String) line: 1157
TestcaseContextListener.contextDestroyed(ServletContextEvent) line: 27
StandardContext.listenerStop() line: 4775
StandardContext.stopInternal() line: 5385
StandardContext(LifecycleBase).stop() line: 232
StandardContext.reload() line: 3739
HostConfig.reload(HostConfig$DeployedApplication) line: 1304
HostConfig.checkResources(HostConfig$DeployedApplication) line: 1236
HostConfig.check(String) line: 1491
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not
available [native method]
NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43
Method.invoke(Object, Object...) line: 483
BaseModelMBean.invoke(String, Object[], String[]) line: 300
DefaultMBeanServerInterceptor.invoke(ObjectName, String, Object[],
String[]) line: 819
JmxMBeanServer.invoke(ObjectName, String, Object[], String[]) line: 801
ManagerServlet.check(String) line: 1460
ManagerServlet.deploy(PrintWriter, String, ContextName, String, boolean,
StringManager) line: 906
ManagerServlet.doGet(HttpServletRequest, HttpServletResponse) line: 344
ManagerServlet(HttpServlet).service(HttpServletRequest,
HttpServletResponse) line: 618
ManagerServlet(HttpServlet).service(ServletRequest, ServletResponse) line:
725
ApplicationFilterChain.internalDoFilter(ServletRequest, ServletResponse)
line: 291
ApplicationFilterChain.doFilter(ServletRequest, ServletResponse) line: 206
WsFilter.doFilter(ServletRequest, ServletResponse, FilterChain) line: 52
ApplicationFilterChain.internalDoFilter(ServletRequest, ServletResponse)
line: 239
ApplicationFilterChain.doFilter(ServletRequest, ServletResponse) line: 206
SetCharacterEncodingFilter.doFilter(ServletRequest, ServletResponse,
FilterChain) line: 108
ApplicationFilterChain.internalDoFilter(ServletRequest, ServletResponse)
line: 239
ApplicationFilterChain.doFilter(ServletRequest, ServletResponse) line: 206
StandardWrapperValve.invoke(Request, Response) line: 219
StandardContextValve.invoke(Request, Response) line: 106
BasicAuthenticator(AuthenticatorBase).invoke(Request, Response) line: 613
StandardHostValve.invoke(Request, Response) line: 142
ErrorReportValve.invoke(Request, Response) line: 79
AccessLogValve(AbstractAccessLogValve).invoke(Request, Response) line: 610
StandardEngineValve.invoke(Request, Response) line: 88
CoyoteAdapter.service(Request, Response) line: 516
Http11NioProcessor(AbstractHttp11Processor).process(SocketWrapper<S>) line:
1086
Http11NioProtocol$Http11ConnectionHandler(AbstractProtocol$AbstractConnectionHandler).process(SocketWrapper<S>,
SocketStatus) line: 659
Http11NioProtocol$Http11ConnectionHandler.process(SocketWrapper<NioChannel>,
SocketStatus) line: 223
NioEndpoint$SocketProcessor.doRun(SelectionKey, NioEndpoint$KeyAttachment)
line: 1558
NioEndpoint$SocketProcessor.run() line: 1515
ThreadPoolExecutor(ThreadPoolExecutor).runWorker(ThreadPoolExecutor$Worker)
line: 1142
ThreadPoolExecutor$Worker.run() line: 617
TaskThread$WrappingRunnable.run() line: 61
TaskThread(Thread).run() line: 745
The ClassLoader gives up on loading the class. The WebResourceSet it would
have used to load the class from (in the method
StandardRoot.getResourceInternal) is a DirResourceSet pointed to the exploded
directory path - e.g. /path/to/tomcat/webapps/ClassNotFoundGenerator/. The
path it generates in DirResourceSet.getResource is
/path/to/tomcat/webapps/ClassNotFoundGenerator/WEB-INF/classes/com/avadyne/ThisClassNotFound.class
- the path is correct. The file doesn't exist, and it returns a new
EmptyResource(root, path, f).
When the WebappClassLoader attempts to load the class, the .class file (and the
entire exploded directory) is not on the disk. The bug occurs during these
frames of the ClassNotFoundError stack trace (8.0.20).
java.lang.NoClassDefFoundError: com/avadyne/ThisClassNotFound
...
at
org.apache.catalina.core.StandardContext.reload(StandardContext.java:3739)
at org.apache.catalina.startup.HostConfig.reload(HostConfig.java:1304)
at
org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1236)
...
HostConfig.checkResources:1231 deletes the exploded directory
HostConfig.checkResources:1236 calls into StandardContext.reload
StandardContext.reload:3739 eventually invokes the ServletContextListeners
Once the contextDestroyed listeners are executed, the .class file doesn't exist
(HostConfig.checkResources deleted it).
It is unsafe for HostConfig.checkResources to delete the unpacked directory
before the context is stopped. However, WebappClassLoader is correct to throw
a ClassNotFoundError, since the class doesn't exist on disk.
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