Users of an on-line banking app are getting java exceptions when the applet they choose is loading.
Java is downloading the jar files that the applet has requested into the client's cache.
The java console log shows that only every other jar file is being loaded into cache.
When a method from a jar that does not get downloaded is accessed, the user gets a java exception.

e.g.
network: Connecting https://us.xyz.com/proxy/.../TMSControl.class with cookie...

java.lang.RuntimeException: java.lang.NullPointerException
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.getHeaderField(Unknown Source)
        at java.net.HttpURLConnection.getResponseCode(Unknown Source)
        at sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(Unknown Source)
        at sun.applet.AppletClassLoader.getBytes(Unknown Source)
        at sun.applet.AppletClassLoader.access$100(Unknown Source)
        at sun.applet.AppletClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        ...