Christopher's Proguard solution is the best, but if for any reason you don't like Proguard, here is a very low-tech solution:
Comment logs:
find . -name "*\.java" | xargs grep -l 'Log\.' | xargs sed -i 's/Log\./;\/\/ Log\./g'
Uncomment logs:
find . -name "*\.java" | xargs grep -l 'Log\.' | xargs sed -i 's/;\/\/ Log\./Log\./g'
A constraint is that your logging instructions must not span over multiple lines.
(Execute these lines in a UNIX shell at the root of your project. If using Windows, get a UNIX layer or use equivalent Windows commands)
