We were already using Proguard for obfuscation and we tried to use it to reduce the size of the JDK as well. If my memory serves well the main problem was that the results weren't good enough results because Proguard was being conservative and keeping a lot of stuff that we know we didn't need, but static analysis indicated that it could potentially be used.
Also, Proguard's config is pretty complicated and the results are hard to understand. Our approach (openjdk-trim) is dumb simple: unpack the java runtime jars, use rsync to filter out entire directories we don't need, pack it back.
It's a simple, brute-force approach compared to Proguard's advanced static analysis, but in this case it gives better results. Maybe a good example of "worse is better".
Also, Proguard's config is pretty complicated and the results are hard to understand. Our approach (openjdk-trim) is dumb simple: unpack the java runtime jars, use rsync to filter out entire directories we don't need, pack it back.
It's a simple, brute-force approach compared to Proguard's advanced static analysis, but in this case it gives better results. Maybe a good example of "worse is better".