When people surf random websites they can expect to get pwned. They should not expect any AV software, or any amount of turning off or any government advice to save them. Java will be safe if downloaded from any reasonable site, obviously not porn or russian sites with miracle cures, or making $200 an hour surfing or anything else like that.
HUH? Seriously, you didn't read the alert or you don't understand it.
Don't care what YOU do, but the alert is real, dangerous and is a serious exploit of Java. Others should take heed. Or not.