No, Java is not routinely needed - some websites may try to make use of it, but even if you did install it I would recommend explicitly denying it to be used on websites. I'd actively avoid installing it unless you needed it (in most cases).
If you have it installed already and want to keep it, then yes you should always keep it up to date (vulnerabilities are often found), but if you're not using it for anything then I would uninstall it and rid yourself of an attack vector.
