If you want to decompile the whole tree of JAVA classes,
use the following command:
jad -o -r -sjava -dsrc tree/**/*.class
This command decompiles all .class files located in all
subdirectories of 'tree' and creates output files in subdirectories
of 'src' according to package names of classes. For example, if file
'tree/a/b/c.class' contains class 'c' from package 'a.b', then
output file will have a name 'src/a/b/c.java'.