[RetroGuard-v2.1.x and later]
RetroGuard can remove unused classes during obfuscation.
When including a Java library in your obfuscated jar, large parts of
the library may be unused by your particular application.
These unused methods, fields, and even whole classes add unnecessary bulk
to your deployed software. To have RetroGuard trim this unused code during
obfuscation, add a script line:
.option Trim
Since this trimming occurs at the Java class level some of the results,
while correct, may be unexpected. In particular, references to static final
fields (constants) are usually optimized away during compilation. These
fields will therefore be removed even though they seem to be referenced in
the Java source. This has no adverse effect at the Java class-file level.
Trim and Patch Files
Use of .option Trim is not recommended when generation of
patch files is planned. See
Creating patch files
for more details on patch file generation. This is because of the difficulty
in working out which classes would need to be included in the patch jars.
With trimming enabled this would be a mixture of updated classes, along with
classes which were partially or fully trimmed in the original version but
which are now referenced in updated code.
Trim and Reflection
RetroGuard's .option Trim has no awareness of reflection
methods, and will therefore remove code which is only referenced by reflection.
The solution is to preserve class, method, or field identifiers which are
referenced by reflection, by including them in the RetroGuard script file.
