I noticed the same thing. According to http://blogs.oracle.com/java/entry/java_7_questions_answers, the fix is only in "current builds of JDK 7 Update 1". I imagine you can download it from the OpenJDK site somehow, but it does not seem that JDK 7 Update 1 has actually been released yet.

For a few weeks when I was young (the mid 80's) I kept some mercury (about 10 mL) which I had obtained from a broken thermometer at the hospital in my bedroom. I found that I was having a bit of breathing difficulty a few weeks later, and had my mother dispose of it for me. I suspect it was evaporating like your sample. I've never read up on the potential for gaseous mercury to do this, but even today I strongly suspect that the effect I observed was real.