jboss_init_solaris.sh simply checks whether a JBoss instance is running and complains if it already is, which means that you can't use it to start multiple instances properly.

I haven't fully tested it out, but replacing

if [ "x${isJBossRunningPid}" != "x" ]; then
return 0
fi

with the following would be more reliable

if [ "x${isJBossRunningPid}" != "x" ]; then
args=`pargs -a ${JBossPid}`
if [ "x${args}" == "x" ] || `echo ${args} | grep "-c ${instance}"`; then
return 0
fi
fi