What do I need to do to get LiveConnect working again?

Question

Years ago I wrote a Java Web Start application in NetBeans that performs a simple file upload task. For years I had it as a self-signed applet but finally caved and bought a signing certificate. I've got it all signed now, but I'm running into a new problem.

One of the main class' public methods gets called by JavaScript. However, it seems to have stopped working. When I try calling this method manually in Firebug, here's the message I get back:

Error: Liveconnect call for Applet ID 8 is not allowed in this JVM instance.

UPDATE: Here's the version of the error that I get when I try this in Chrome:

Error calling method on NPObject.

I am already using the most up-to-date version of the Java plugin (7u51), so what gives? This applet used to work, but now apparently it no longer does. Do I need to add something special to the code? Or change a setting in the way it's compiled by NetBeans?

Answer 1

I figured it out; I found some forum posts that mentioned I had to update my Manifest file. Apparently Oracle recently changed the way Liveconnect works so you have to be explicit about allowing subdomains that can call the applet.

The information on that is here, and basically you have to add the Caller-Allowable-Codebase directive to the Manifest file. Fortunately it can be set to a wildcard, which is what I ended up doing. Apparently you're also supposed to set Application-Name along with it in the manifest file, and you're specifically NOT supposed to include Trusted-Library true. I don't really know why or what that does, but I was able to adjust my manifest file and everything seems to work again!