Simple question for today !

I am working on converting a public domain code suite (http://www.JavaSeis.org) to use openmpi rather than mpiJava.
So far, all has gone well, other than the usual issues with getting all the paths and variables straightened out.
For automation purposes, I would like to be able to specify everything from the command line, rather than using files.

Why does this command work:

chuck-> /usr/local/bin/mpirun -np 1 /usr/bin/java -version
java version "1.6.0_37"
Java(TM) SE Runtime Environment (build 1.6.0_37-b06-434-10M3909)
Java HotSpot(TM) 64-Bit Server VM (build 20.12-b01-434, mixed mode)

But this one does not:

chuck-> /usr/local/bin/mpirun -np 1  -host localhost /usr/bin/java -version
--------------------------------------------------------------------------
All nodes which are allocated for this job are already filled.
--------------------------------------------------------------------------

Nor does this one:

chuck-> cat hostfile
localhost slots=2

chuck->/usr/local/bin/mpirun -np 1 -hostfile hostfile /usr/bin/java -cp . -version
--------------------------------------------------------------------------
All nodes which are allocated for this job are already filled.
--------------------------------------------------------------------------


For reference:

chuck-> /usr/local/bin/mpirun -version
mpirun (Open MPI) 1.7rc5

Report bugs to http://www.open-mpi.org/community/help/

chuck-> uname -a
Darwin iMac.local 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun  7 16:32:41 PDT 2011; root:xnu-1504.15.3~1/RELEASE_X86_64 x86_64

My build was done with "configure --enable-mpi-java --prefix=/usr/local".

Thanks for any insight !

Chuck Mosher
chuckmosher@JavaSeis.org