For several weeks security experts have warned that the Blackhole exploit toolkit was about to gain a weapon for attacking unpatched holes in Java.
New Java-based Web attack discovered
Java moves frustrate users, vendors
One problem is that PC users don't upgrade Java as often as they should -- if they do at all. That's a problem because Java is one of the first places hackers look to exploit. Related to that is the large number of computer users around the world who have no anti-malware defences on their machines.
Corp. took over control of Java when it bought Sun Microsystems in 2009.