Oracle has released a new Version 6 Update 23 of its Java software (which it acquired along with Sun Microsystems). This version fixes more than 50 identified bugs, including a number of security fixes. It also incorporates updated time zone information and better support for languages that are written right to left. Further information is in the Release Notes; details of the bugs fixed are on the Bug Fix page.
The new version is available for Windows, Linux, and Solaris (SPARC and Intel) systems, and can be downloaded here; alternatively, the update mechanism included with the software can be used. (Mac users should note that Apple maintains its own versions of Java, and typically takes at least a few weeks to get the latest updates.) As I noted in an earlier post, it is not clear that everyone needs to install Java. However, if you do have it installed, I recommend installing this update as soon as you conveniently can, because of the security fixes.