http://i18n-u1-26c.sfbay.sun.com:8080/jaws-i18n/test/bat/hello-i18n.html
Launching this testcase, following exception is thrown.
This is reproduced both on Solaris 10 and Windows 2003.
Introduced in Mustang b46.

java.lang.ClassCastException: java.io.File cannot be cast to com.sun.deploy.cache.CachedJarFile
at com.sun.deploy.cache.CacheEntry$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.deploy.cache.CacheEntry.getJarFile(Unknown Source)
at com.sun.deploy.net.DownloadEngine.getCachedJarFile(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source)
at sun.misc.URLClassPath$JarLoader.getJarFile(URLClassPath.java:628)
at sun.misc.URLClassPath$JarLoader.access$700(URLClassPath.java:538)
at sun.misc.URLClassPath$JarLoader$1.run(URLClassPath.java:586)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath$JarLoader.ensureOpen(URLClassPath.java:578)
at sun.misc.URLClassPath$JarLoader.<init>(URLClassPath.java:559)
at sun.misc.URLClassPath$3.run(URLClassPath.java:331)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:320)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:297)
at sun.misc.URLClassPath.access$000(URLClassPath.java:59)
at sun.misc.URLClassPath$1.next(URLClassPath.java:194)
at sun.misc.URLClassPath$1.hasMoreElements(URLClassPath.java:205)
at java.net.URLClassLoader$3$1.run(URLClassLoader.java:393)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader$3.next(URLClassLoader.java:390)
at java.net.URLClassLoader$3.hasMoreElements(URLClassLoader.java:415)
at sun.misc.CompoundEnumeration.next(CompoundEnumeration.java:27)
at sun.misc.CompoundEnumeration.hasMoreElements(CompoundEnumeration.java:36)
at sun.misc.Service$LazyIterator.hasNext(Service.java:255)
at sun.util.LocaleServiceProviderPool$1.run(LocaleServiceProviderPool.java:107)
at java.security.AccessController.doPrivileged(Native Method)
at sun.util.LocaleServiceProviderPool.<init>(LocaleServiceProviderPool.java:104)
at sun.util.LocaleServiceProviderPool.getPool(LocaleServiceProviderPool.java:86)
at java.text.DateFormatSymbols.getInstance(DateFormatSymbols.java:275)
at java.text.SimpleDateFormat.<init>(SimpleDateFormat.java:445)
at sun.net.www.protocol.http.HttpURLConnection.writeRequests(HttpURLConnection.java:381)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:968)
at com.sun.deploy.net.HttpUtils.followRedirects(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doRequest(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doGetRequestEX(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source)
at sun.misc.URLClassPath$JarLoader.getJarFile(URLClassPath.java:628)
at sun.misc.URLClassPath$JarLoader.access$700(URLClassPath.java:538)
at sun.misc.URLClassPath$JarLoader$1.run(URLClassPath.java:586)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath$JarLoader.ensureOpen(URLClassPath.java:578)
at sun.misc.URLClassPath$JarLoader.<init>(URLClassPath.java:559)
at sun.misc.URLClassPath$3.run(URLClassPath.java:331)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:320)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:297)
at sun.misc.URLClassPath.access$000(URLClassPath.java:59)
at sun.misc.URLClassPath$1.next(URLClassPath.java:194)
at sun.misc.URLClassPath$1.hasMoreElements(URLClassPath.java:205)
at java.net.URLClassLoader$3$1.run(URLClassLoader.java:393)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader$3.next(URLClassLoader.java:390)
at java.net.URLClassLoader$3.hasMoreElements(URLClassLoader.java:415)
at sun.misc.CompoundEnumeration.next(CompoundEnumeration.java:27)
at sun.misc.CompoundEnumeration.hasMoreElements(CompoundEnumeration.java:36)
at sun.misc.Service$LazyIterator.hasNext(Service.java:255)
at sun.util.LocaleServiceProviderPool$1.run(LocaleServiceProviderPool.java:107)
at java.security.AccessController.doPrivileged(Native Method)
at sun.util.LocaleServiceProviderPool.<init>(LocaleServiceProviderPool.java:104)
at sun.util.LocaleServiceProviderPool.getPool(LocaleServiceProviderPool.java:86)
at java.text.DateFormatSymbols.getInstance(DateFormatSymbols.java:275)
at java.text.SimpleDateFormat.<init>(SimpleDateFormat.java:445)
at sun.net.www.protocol.http.HttpURLConnection.writeRequests(HttpURLConnection.java:381)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:968)
at com.sun.deploy.net.HttpUtils.followRedirects(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doRequest(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doGetRequestEX(Unknown Source)
at com.sun.deploy.net.DownloadEngine.isUpdateAvailable(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(Unknown Source)
at sun.misc.URLClassPath$JarLoader.getJarFile(URLClassPath.java:628)
at sun.misc.URLClassPath$JarLoader.access$700(URLClassPath.java:538)
at sun.misc.URLClassPath$JarLoader$1.run(URLClassPath.java:586)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath$JarLoader.ensureOpen(URLClassPath.java:578)
at sun.misc.URLClassPath$JarLoader.<init>(URLClassPath.java:559)
at sun.misc.URLClassPath$3.run(URLClassPath.java:331)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:320)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:297)
at sun.misc.URLClassPath.getResource(URLClassPath.java:167)
at java.net.URLClassLoader$1.run(URLClassLoader.java:192)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at sun.applet.AppletClassLoader.findClass(AppletClassLoader.java:155)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.applet.AppletClassLoader.loadClass(AppletClassLoader.java:127)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at sun.applet.AppletClassLoader.loadCode(AppletClassLoader.java:618)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:760)
at sun.plugin.AppletViewer.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:689)
at sun.applet.AppletPanel.run(AppletPanel.java:361)
at java.lang.Thread.run(Thread.java:608)