Some of my buddies from Geotools have done work on the JSR that provides a standard way to work with measurements and measurement units. That is definitely something a surveyor (and most GIS junkies) would be interested in. I had a hard time locating a JAR of the JSR-275 implementation, but with some help from Simone at Geotools I found its location in a maven repository.
You can download it here:
The source code and javadocs are there as well.
Here is the home page for the JSR itself:
Here is a link to the PDF of the spec for the JSR:
The Sunburned Surveyor