Blijkbaar dien je dat via synaptic te doen. Het onderstaande voorbeeld verwijdert wel alle java-versies!
Remove the old version
First you'll want to remove the old version. If it's installed from the repositories, do it like this:
System - Administration - Synaptic Package Manager
Query: sun java
Tick all installed packages and choose complete removal.
If it's installed manually in /opt/java, simply delete the folder /opt/java. If you don't know how to do that, see the bottom of this page (under the header Removal).