I found a message in a thread and another message that may be of interest.

I may have also misunderstood some of the lineage. Apparently, the Self people wrote a Java VM in Self, and found it to be faster than the Sun-produced Java VMs, so that became the basis of Hotspot, which is now at the core of the current Sun Java VM. Whether any of the Self Java VM code survived intact, I cannot tell.

-- Randal L. Schwartz, Perl hacker