Would you recoomend this project?
FlameCalc is an RPN caclulator by the good folks at the Flame Design Group. It is written in Java with the intent to remain GCJ compatible and eventually evolve into a useful RPN language. HTTP-loaded scripts and Java plugins are supported.
You can download file releases of FlameCalc project from List of release files
System RequirementsOperating System: MacOSX, POSIX (Linux,BSD,Solaris etc..), Linux, OS Independent
List of release files