With 6u14, under MultiJRE scenarios, applets requesting 142 family fail to load by throwing following exception. Issue is not reproducible with 6u10 and 6u12.
java.lang.NoClassDefFoundError: java/net/ResponseCache

at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(Unknown Source)

at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFileInternal(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 sun.plugin2.applet.Plugin2ClassLoader$2.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at sun.plugin2.applet.Plugin2ClassLoader.findClassHelper(Unknown Source)

at sun.plugin2.applet.JNLP2ClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)

at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)

at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)

Exception: java.lang.NoClassDefFoundError: java/net/ResponseCache
Steps to reproduce:
-----------------
- Install 6u14,5u18 and 1.4.2_20 on the machine

- Try to load the following applet:
http://sqeweb.sfbay.sun.com/deployment2/jitu/deployment_mustang_exec_ws/deployment/src/plugin/MultiJRE/MultiJRE/html/auto/MultiJREFamily142150Installed/JREMutliFamilyJNLP.html

- If 1.4.2 applet fails to load by throwing exception mentioned above then bug is reproduced