embedded and threaded - in java

Hi!

    Has anyone embedded perl in java with threads or multiple
interpreters?

    I'm trying to build something based on JPerl
(http://search.cpan.org/author/SBALA/jp_beta_1/) and I think I'm
running up against my clue barrier - I'm seeing segfaults and panics
("panic: top_env") when I try to run stuff, even with a single thread.

    I sprinkled in PERL_SET_CONTEXTs liberally, pretty much at the
beginning of any jperl function that uses a perl_ function or a perl
macro...

    Tips would be terribly appreciated.  I'm using perl5.8.0 and java
1.3 (hotspot jvm) on solaris 8.  Here's a stupid question to get you
started: My java is linked against libthread; perl seems to prefer
libpthread.  Do I need to make perl use libthread?  It looks like 
libpthread uses libthread itself...

Also:
    - Do I need to "use threads" or any thread functions in my perl?
    I haven't yet - I've started with a single interp called from a
    single java thread.  But I read in one older message that perl
    takes shortcuts if it doesn't think the thread stuff will actually
    be used?

    - Would all this be simpler with a mere multiplicity perl instead
      of a multiplicity-ithreads perl?  I think I'd still need to be
      able to call each interpreter from multiple threads to get the
      performance characteristics I'm looking for.

Thanks.  :(
Meg Crocker