with
If you use Heap Analysis Tool (HAT), this is a great news for you. Mustang (Java SE 6) (build 51 onwards) includes HAT in $JDK/bin directory. This is called jhat - Java Heap Analysis Tool. So, you don't need to download HAT separately! JDK will include it as part of standard distribution.
Besides we are adding new features to jhat -- stay tuned! I'll blog more about it when the bits become available...