Writing Exclusions (Skidfuscator >= 2.0.0)

GhastAbout 2 min

Writing Exclusions (Skidfuscator >= 2.0.0)

Understanding exclusions might be tricky at first, but trust me, it is quite easy once you get the hang of it. First and foremost, it's important to understand basic regex.

Basics of Regex (Regular expressions)

  • Here's a basic string to match everything:

So the following would happen:

abozeofez // Matches!
zeigzoegze // Matches!

  • To match any string which contains "roar", you'd have

So the following would happen:

roar // Matches!
asdafroar // Matches!
grrr // No match!

To match any string which begins with "uwu", you'd have:


So the following would happen:

kitty-uwu // Matches!
uwu-kitty // No match!

If you'd like to read more about Regex, find out here: Regex tutorialopen in new window

Writing exclusions

Now, you'll want to create an exclusion file, and here you'll be able to mess around. Skidfuscator reads inclusions and exclusions the same way: if it matches a regex pattern, it will not be read or obfuscated.


Writing an exclusion is relatively simple. By using regex forward matching as seen below, you are able to match any type of class. Remember to escape any "/" with a "\" to prevent Regex from comitting seppuku and you spending hours figuring out what's wrong.

// This will match any method with the name "main"
// This will match any method which starts with "com.apache" 
// (any class name replaces the "." with "/"

Multiple exclusions

To be able to exclude for example several methods, or packages, it's quite simple really! All you have to do is create a new line and add the new exemption 😃

class{^com\/apache} // Matches apache
class{^com\/google} // Matches google


As opposed to exclusions, you may want to only include a particular set of classes or a package in your obfuscated jar. Fret not, this is possible, albeit a little more complicated.

// This will match all classes of the package "com.example"

// This will match all classes of the package "com.example" and 
// all of the classes of the package "com.eclipse". 
// You may add as many packages as you wish with the "|" argument.

Debugging Exclusions

I strongly recommend using a regex debugger, such as Regex101open in new window, to be able to figure out what matches and what does not.

All class names, by default, follow the format "package1/package2/class1". Whilst you may see in the JVM it is formatted differently, in the case of Skidfuscator, the above format was decided to be the most effective and reflective of Jar/Zip file hierarchy.