Wow that was a quick update.
Changelog : http://java.sun.com/javase/6/webnotes/6u16.html
Changes in 1.6.0_16 (6u16)
The full internal version number for this update release is 1.6.0_16-b01 (where "b" means "build"). The external version number is 6u16.
OlsonData 2009i
6u16 contains Olson time zone data version 2009i. For more information, refer to Timezone Data Versions in the JRE Software .
Security Baseline
6u16 specifies the following security baselines for use with Java Plug-in technology:
JRE Family Version Java SE Security Baseline Java SE for Business Security Baseline 5.0 1.5.0_20 1.5.0_201.4.2 1.4.2_19 1.4.2_22
In December, 2008, Java SE 1.4.2 reached its end of service life with the release of 1.4.2_19. Future revisions of Java SE 1.4.2 (1.4.2_20 and above) include the Access Only option and are available to Java SE for Business subscribers.
For more information about the security baseline, see Deploying Java Applets With Family JRE Versions in Java Plug-in for Internet Explorer .
Bug Fixes
This feature release does not contain any new fixes for security vulnerabilities to its previous release, Java SE 6 Update 15. Users who have Java SE 6 Update 15 have the latest security fixes and do not need to upgrade to this release to be current on security fixes.