Details here http://java.dzone.com/articles/latest-java-update-fixes?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+javalobby/frontpage+(Javalobby+/+Java+Zone)
Basic problem involved change of a string from Sun to Oracle and Eclipse depending on that string to control some memory settings. We all probably have some code that checks vendor strings of some type and it is so easy to get bitten by them. I know I was checking for Vista in some areas and once Win7 came out I needed to check for Win7 and Vista as the combobox painting is the same between them.
Hopefully they will be able to update the string at some point, they do own Java now, and the Eclipse team can come out with a solution as they appear to be the ones that actually cheated.