I upgraded Slack from 12.1 to current some time ago and have kept it up to date since.
The problem I have with java is, it seems to work fine in a browser, that it doesn't work from a terminal.
Trying to run ControlPanel I get:
ControlPanel: Error: Invalid link or copy:
Allso, java apps I can run from a browser but not from a link like:
javaws
https://fx1.oanda.com/java/beta.jnlp
If I downgrade to java.6_U6 everything works fine.
cheers!