determining icon theme

[Michael Brewer-Davis]

I apologize if this is a silly question, but...

Is there a cross-dm way of determining the current icon theme?  The icon 
theme and naming specifications talk about searching relative to the 
current theme, but I can't seem to determine (from a shell or in C, say) 
what the current theme is.

My end goal: I'm attempting to use themed icons within my program (which 
is mostly Java, actually).  I haven't found any tidy ways of grabbing an 
icon in the current theme for a given file extension or mime type.

Best,
Michael