I recently installed ATG 2007.1 with no patches on JBoss 4.0.5.GA.  When I started it up I continually saw these illegal access errors.

16:01:24,296 INFO  [WebappClassLoader] Illegal access: this web application instance has been stopped already.  Could not load org.apache.log4j.Level.
  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1241)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1201)
        at org.apache.commons.logging.impl.Log4jProxy$1.run(Log4jProxy.java:66)
        at java.security.AccessController.doPrivileged(Native Method)
        at org.apache.commons.logging.impl.Log4jProxy.threadContextClassLoader(Log4jProxy.java:88)
        at org.apache.commons.logging.impl.Log4jProxy.(Log4jProxy.java:94)
        at org.apache.commons.logging.impl.Log4JLogger.(Log4JLogger.java:39)
        at sun.reflect.GeneratedConstructorAccessor22.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
        at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
        at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:372)
        at atg.nucleus.logging.commons.CommonsLoggingLogListener.logEvent(CommonsLoggingLogListener.java:106)
        at atg.nucleus.GenericService.sendLogEvent(GenericService.java:291)
        at atg.nucleus.GenericService.logInfo(GenericService.java:737)
        at atg.nucleus.GenericService.logInfo(GenericService.java:715)
        at atg.ui.j2edit.model.CachingJ2eeArchiveDirectoryAgent.updateCacheData(CachingJ2eeArchiveDirectoryAgent.java:513)
        at atg.ui.j2edit.model.CachingJ2eeArchiveDirectoryAgent.performScheduledTask(CachingJ2eeArchiveDirectoryAgent.java:573)
        at atg.service.scheduler.ScheduledJob.runJobs(ScheduledJob.java:441)
        at atg.service.scheduler.Scheduler$2handler.run(Scheduler.java:760)

Fortunately this is a common problem and there are many support incidents about it.  Problem Report #144586 says that the problem occurs if:

1. say “Yes” to deploying Quincy Fund during installation
2. use startDynamoOnJBoss to run any other application

The work around is to remove Quincy Funds.ear from the JBoss deployment directory.  Or just don’t install Quincy Funds.

If you need to run the Quincy Funds demo then the Error running Quincy Funds demo on JBoss document suggests:

1. stop the server
2. delete the ATGDAF.ear from the JBoss installation
3. start JBoss with the run.bat|sh command; the Quincy Funds demo is automatically started

For further reading please see How to use the startDynamoOnJBOSS script and JBoss configurations to run an application.  You may need to have an active ATG support contract to view these and other ATG support documents referenced in this article.