Because of the flexibility of the programming language and its widespread use on web sites, it is a perfect target for hackers. Last year Microsoft reported that Java was exploited in malware more often than Adobe Reader and Flash (Microsoft Security Intelligence Report Volume 11).
So how do you update your computer’s Java? For Windows folks, the easiest thing to do is go to www.java.com and click on update. You can also go to Start, Control Panel, Java and check your version there (latest version as of May 8 is Version 6 Update 31). For Mac folks, you get your java updates from Apple so be sure to run Apple updates when they arrive. I’m sure after the whole Flashback affair, Apple will be a little timely with their Java updates.