Name: gm110360 Date: 09/05/2003
FULL PRODUCT VERSION :
java version "1.4.2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-b28)
Java HotSpot(TM) Client VM (build 1.4.2-b28, mixed mode)
FULL OS VERSION :
Microsoft Windows 2000 [Version 5.00.2195]
EXTRA RELEVANT SYSTEM CONFIGURATION :
Microsoft Internet Explorer 6.0 SP1 [Version 6.0.2800.1106]
IBM HTTP Server 2.0.42
Plug-in JRE configured as "JRE 1.4.2 in C:\Program Files\Java\j2re1.4.2"
A DESCRIPTION OF THE PROBLEM :
When downloading a web based application containing java applets the java plugin occasionally throws a ConcurrentModificationException when the applet jar file has been updated at the web server. Application startup fails when the exception is thrown.
STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Attempts to produce a pared-down version of the web application suitable for inclusion here have failed to reproduce the problem. Even our web application does not cause the problem to occur in a repeatable manner, although the problem does occur daily.
EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A ConcurrentModificationException should not be thrown.
ACTUAL -
See stack trace for details.
ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.util.ConcurrentModificationException at java.util.AbstractList$Itr.checkForComodification(Unknown Source) at java.util.AbstractList$Itr.remove(Unknown Source) at sun.plugin.cache.JarCache.match(Unknown Source) at sun.plugin.cache.JarCache.getMatchingFile(Unknown Source) at sun.plugin.cache.CachedJarLoader$4.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.plugin.cache.CachedJarLoader.getCacheFile(Unknown Source) at sun.plugin.cache.CachedJarLoader.<init>(Unknown Source) at sun.plugin.cache.JarCache.get(Unknown Source) at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source) at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source) at sun.misc.URLClassPath$JarLoader.getJarFile(Unknown Source) at sun.misc.URLClassPath$JarLoader.<init>(Unknown Source) at sun.misc.URLClassPath$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.misc.URLClassPath.getLoader(Unknown Source) at sun.misc.URLClassPath.getLoader(Unknown Source) at sun.misc.URLClassPath.getResource(Unknown Source) at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at sun.applet.AppletClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.applet.AppletClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.applet.AppletClassLoader.loadCode(Unknown Source) at sun.applet.AppletPanel.createApplet(Unknown Source) at sun.plugin.AppletViewer.createApplet(Unknown Source) at sun.applet.AppletPanel.runLoader(Unknown Source) at sun.applet.AppletPanel.run(Unknown Source) at java.lang.Thread.run(Unknown Source)
REPRODUCIBILITY :
This bug can be reproduced occasionally.
---------- BEGIN SOURCE ----------
The main focus of the web based application, from a java perspective, is that two applets are being accessed from a single JAR file. See the two <object> tags in the following launch page content for details:
<?xml version="1.0" ?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Web Based Application</title>
<!-- Launch page include Files (JScript) -->
<link rel="stylesheet" href="css/Styles.css" type="text/css" />
</head>
<body class="index" onload="windowOnload();" onunload="windowOnUnload();">
<script src="menu/menuLoad.js" type="text/javascript"></script>
<object id="FirstComponent"
classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
align="top"
width="0"
height="0">
<param name="code" value="uk.co.xxx.yyy.zzz.applet.AppletOne.class" />
<param name="codebase" value="." />
<param name="archive" value="AppletsArchive.jar,axis.jar,commons-discovery.jar,commons-logging.jar,jaxrpc.jar,log4j-1.2.8.jar,saaj.jar,wsdl4j.jar,xerces.jar,xalan.jar,commons-logging-api.jar,j2ee.jar" />
<param name="type" value="application/x-java-applet;version=1.3" />
<param name="scriptable" value="true" />
</object>
<object id="SecondComponent"
classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
align="top"
width="0"
height="0">
<param name="code" value="uk.co.xxx.yyy.zzz.applet.AppletTwo.class" />
<param name="codebase" value="." />
<param name="archive" value="AppletsArchive.jar,commons-logging.jar,log4j-1.2.8.jar,xerces.jar,xalan.jar,commons-logging-api.jar" />
<param name="type" value="application/x-java-applet;version=1.3" />
<param name="scriptable" value="true" />
</object>
<!-- Rest of launch page content -->
</body>
</html>
---------- END SOURCE ----------
CUSTOMER SUBMITTED WORKAROUND :
The current workaround involves clearing the plugin cache every time before starting the web application.
(Incident Review ID: 198644)
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