Did you install Java 6, which Linc Davis gave you a link for? Even if you did, it may not help since the message is specifically stating "web content".
Version 7 of Oracle's Java won't even run under Yosemite. OS X itself blocks its use. You shouldn't even be able to have all of the versions you list all installed at the same time. Each should overwrite the other.
If you feel you must try, install Oracle's latest version of Java, which as you already know, is version 8, release 45.
The real question though is, what web site are you visiting that this message appears? It could be a site trying to get the now extinct Flashback Trojan to install on your Mac, which Yosemite is patched against. The web site doesn't know this, so keeps trying every time you visit that site.
And the bigger question is, why do you need Java? If you have no Java apps on your drive which require Java to run, and you do not visit any trusted web sites you commonly use that require Java to function, then there's no need to have it installed at all. If that's the case, as Linc mentioned, remove it.
For Java 8, all you need to do is put the file JavaAppletPlugin.plugin in the trash, then open the System Preferences, right click on the Java icon, and choose to remove it (the System Preference item is nothing more than an alias which points to the JavaAppletPlugin.plugin file).