Linux (Ubuntu) Java plugin and console

I'm trying to test a Java applet in Firefox in Ubuntu 10.10. Unfortunately it doesn't work out of the box. I have two issues:

1. By default the IcedTea plugin was used, which I don't trust. I installed sun-java6-plugin but have no idea which one is used by Firefox (and other browsers) now. How can I make sure? Fixed this by simply removing icedtea.
2. I have no console. It's usually accessible via a tray icon in Windows, but not here (maybe this will automatically be fixed by #1 though No it wasn't). There's this addon but it doesn't work anymore. Update: I've sort of fixed this by going to the Java control panel and checking "Show Console" in the advanced tab, but now the console always pops up which isn't quite perfect yet.

I'm deploying the applet via JNLP. You can see it here, if it helps. I have sun-java6-jdk as the default Java.

(Sorry if this开发者_开发技巧 question belongs on SuperUser or another site, but I figured that with #2 especially this is a programming related question)

With :

sudo update-alternatives --install "/usr/bin/java" "java" "/opt/java/64/jre1.6.0_20/bin/java" 1
sudo update-alternatives --set java /opt/java/64/jre1.6.0_20/bin/java

You can set the default jre (in this case a 64 bits one)

with:

java -version

you can see the version

With about:plugins you can see which jre firefox is using