> I have java update 11, 7 and 6. Do I need to keep 7 &
> 6 installed on my pc? Or can I uninstall them?
You can usually uninstall them. Some java applications that you have installed might try to use an older version (e.g. update 6) but you should in that case be able to change the configuration for them so that they are using e.g. 11 instead.
Kaj