cannot load applet / application with NULL manifest

exception thrown when loading applet with null manifest

Applet status: exception: null.
java.lang.NullPointerException
    at java.util.jar.Manifest.<init>(Manifest.java:61)
    at com.sun.deploy.cache.ImmutableManifest.<init>(ImmutableManifest.java:21)
    at com.sun.deploy.cache.CachedJarFile.<init>(CachedJarFile.java:64)
    at com.sun.deploy.cache.CacheEntry$2.run(CacheEntry.java:518)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.deploy.cache.CacheEntry.getJarFile(CacheEntry.java:508)
    at com.sun.deploy.net.DownloadEngine.getCachedJarFile(DownloadEngine.java:363)
    at com.sun.deploy.net.DownloadEngine.getCachedJarFile(DownloadEngine.java:344)
    at sun.plugin.PluginURLJarFileCallBack$1.run(PluginURLJarFileCallBack.java:116)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.plugin.PluginURLJarFileCallBack.retrieve(PluginURLJarFileCallBack.java:94)
    at sun.net.www.protocol.jar.URLJarFile.retrieve(URLJarFile.java:186)
    at sun.net.www.protocol.jar.URLJarFile.getJarFile(URLJarFile.java:50)
    at sun.net.www.protocol.jar.JarFileFactory.get(JarFileFactory.java:78)
    at sun.net.www.protocol.jar.JarURLConnection.connect(JarURLConnection.java:104)
    at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(CachedJarURLConnection.java:189)
    at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFileInternal(CachedJarURLConnection.java:144)
    at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(CachedJarURLConnection.java:90)
    at sun.misc.URLClassPath$JarLoader.getJarFile(URLClassPath.java:647)
    at sun.misc.URLClassPath$JarLoader.access$600(URLClassPath.java:538)
    at sun.misc.URLClassPath$JarLoader$1.run(URLClassPath.java:605)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.misc.URLClassPath$JarLoader.ensureOpen(URLClassPath.java:597)
    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 sun.plugin2.applet.Applet2ClassLoader$1.run(Applet2ClassLoader.java:170)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.plugin2.applet.Applet2ClassLoader.findClass(Applet2ClassLoader.java:159)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at sun.plugin2.applet.Applet2ClassLoader.loadCode(Applet2ClassLoader.java:847)
    at sun.plugin2.applet.Applet2Manager.createApplet(Applet2Manager.java:2624)
    at sun.plugin2.applet.Applet2Manager.access$1800(Applet2Manager.java:84)
    at sun.plugin2.applet.Applet2Manager$AppletExecutionRunnable.run(Applet2Manager.java:1209)
    at java.lang.Thread.run(Thread.java:619)
exception


this is regression caused by:
6566201: JNLP ClassLoader performance degraded in 1.6 significantly for the signed(?) jar