Documentation for creating Apple System Services Properties can be found here.
<jarbundler dir="${basedir}" ... >
<service portname="jarBundler"
message="processRequest"
menuitem="JarBundler/Process Request"
sendtypes="NSStringPboardType,NSFilenamesPboardType"
returntypes="NSStringPboardType"
keyequivalent="p"
userdata="a string passed to the method"
timeout="5000" />
<service menuItem="jEdit/Open Files"
message="openFile"
sendTypes="NSStringPboardType,NSFilenamesPboardType"/>
<service menuItem="jEdit/Insert Text"
message="insertSelection"
sendTypes="NSStringPboardType"/>
<service menuItem="jEdit/New Buffer with Text"
message="openSelection"
sendTypes="NSStringPboardType"/>
</jarbundler>