We're trying to determine how to implement a simple plugin framework for a service we are implementing that allows different types of calculators to be "plugged-in".

After reading a number of posts about Java plugin frameworks, it seems like the most common options are:

• OSGI
• "Rolling your own" plugin framework
• The Java Plugin Framework (JPF)
• The Java Simple Plugin Framework (JSPF)

OSGI seems to be more than we need.

"Rolling your own" is ok but it would be nice to reuse a common library.

So we're down to the JPF and JSPF. JPF seems to not be in active development right now.

JSPF seems very simple and really all we need. However I haven't heard much about it. I've only seen one post on StackOverflow about it. Does anyone else have any experience with JSPF? Or any other comments on this design choice?

Update: There isn't necessarily a correct answer to this.. however we're going to go with Pavol's idea as we need just a really, really simple solution. Thanks EoH for the nice guide.