Odds are, unless you're in a business environment with specific needs, you're not going to break anything by uninstalling Java 6. I would uninstall it.

It says that if I uninstall it, some older applications may not be able to run. Is there a way to know if I have (or even need) these "older" applications. Also, is there a list of "older" applications that run java 6 (link would be nice)?

Thanks in advance :)