Input & Output

input defines the path where the target artifact can be found, while output declares where the obfuscated output will be emitted.

These paths are either relative to the location of the configuration file or absolute, except in the case of an absolute base path (e.g. / on most operating systems, or a drive letter root like C:/ on Windows).


input: path/to/application.jar
output: obfuscated-application.jar


libraries is a simple list of JAR files (or directories of JAR files). To use libraries, simply list the JAR files and/or directories that you wish to include. Just like input and output, these paths are relative to the location of the configuration file.

Note: In order for the remapper to function correctly, all libraries upon which the application depends need to be declared in the configuration file. This is because in order to correctly map overridden methods in classes, the obfuscator must process the classes’ inheritance hierarchy to ensure that members that override third-party superclasses are not remapped. (Otherwise, this would lead to AbstractMethodErrors when running the code.)

Element Masks

An element mask defines which elements are to be included and excluded in an obfuscation pass. The global mask is defined by the mask entry in the configuration file, and controls which classes any obfuscation strategy can touch.

input: myproject-1.0.0.jar

mask: # Define the global mask for the obfuscator
  include:                             # We want to limit the scope of obfuscations to only:
    - com/example/myproject/           # - our own project,
    - org/business/proprietarylibrary/ # - and another vendor's library that has been contracted to us.
  exclude:                             # And out of these, we don't want to include:
    - com/example/myproject/api/       # - our public-facing API.

    # Since we're serializing via this class (e.g. via Gson), we don't want to have its field names obfuscated, so we also put it in exclude:
    - com/example/myproject/config/ConfigurationJSONBean

Matching Rules

In an element mask, include and exclude and lists of matching rules.

  • Package: If a rule ends with /, it will match anything starting with the rule. For instance, the rule path/rule/ matches path/rule/One, path/rule/Two, but not other/path/MyClass
  • Wildcard: If a rule ends with *, it will match anything starting with the rule (except the asterisk). For instance, the rule wildcard/rule* matches wildcard/rule/one, wildcard/ruletwothreefour/five, but not wildcard/notrule/anythingelse
  • Literal: Otherwise, a rule will only match anything identical to itself.