Processing resource files
If your application, applet, servlet, library, etc., contains resource files, it may be necessary to adapt their names and/or their contents when the application is obfuscated. The following two options can achieve this automatically:

-adaptresourcefilenames **.properties,**.gif,**.jpg
-adaptresourcefilecontents **.properties,META-INF/MANIFEST.MF

The -adaptresourcefilenames option in this case renames properties files and image files in the processed output, based on the obfuscated names of their corresponding class files (if any). The -adaptresourcefilecontents option looks for class names in properties files and in the manifest file, and replaces these names by the obfuscated names (if any). You'll probably want to adapt the filters to suit your application.