In addition to what everyone else has been said, if you
feel like contributing work on a Java port, go right
ahead! It is an open source project, and that is how
things go. Someone finds something interesting, does it,
and then contributes back.
Incidentally one of the desires of the Parrot project is to
be faster than Perl. So far they claim to be succeeding
with speedups in the range of 20-50% for identical byte
code. (Of course there are enough overall design
differences that we won't have any concrete idea how fast
Perl 6 will or won't be for a long time.)