Don't look too closely at this link because it is full of adverts, but it suggests that there is a security hazard from the older versions of Java6 which have not been uninstalled when newer versions became available. I remember the security problems well. Does anybody know any more about old versions of Java6?
There was a kind of "great divide" regarding security, in a certain revision of Java6. It may have been around Jdk6u21, but I do not recall the full details. The best policy, is that if you really need Java6, get rid of older versions than the latest you can download. That should go for JDK 7,8, or whatever, as well. Because JDKs/JREs executables can be referenced by their paths, and paths can be embedded inside downloads, things could break when you delete one.
Perseverance is best when informed.
Not so fast naughty spawn! I want you to know about