41

Hello I am writing an Android app and I have set up Proguard to obfuscate my application. I however use a classloader to dynamically load different extensions to my application. The problem is that these don't load correctly if their names are changed. How do I keep Proguard from obfuscating specific class names?

Nik
  • 1,033
  • 2
  • 11
  • 28

4 Answers4

46

Use the -keepnames option in your proguard.cfg

Refer to the manual https://www.guardsquare.com/manual/configuration/usage#keepoptions

-keepnames class_specification

Short for -keep,allowshrinking class_specification

Specifies classes and class members whose names are to be preserved, if they aren't removed in the shrinking phase. For example, you may want to keep all class names of classes that implement the Serializable interface, so that the processed code remains compatible with any originally serialized classes. Classes that aren't used at all can still be removed. Only applicable when obfuscating.

muetzenflo
  • 5,653
  • 4
  • 41
  • 82
Zaid Daghestani
  • 8,555
  • 3
  • 34
  • 44
  • Ok is there a way to do it with a whole package? – Nik Jun 10 '12 at 20:12
  • Yes, you use the * wildcard. ie, -keepnames com.randompackage.lol.* Will keep all classes in lol – Zaid Daghestani Jun 10 '12 at 20:15
  • 4
    I have tried that and eclipse returns error 1. Are you sure i dont have to do -keepnames class com.randompackage.lol.ClassName ? I have tried this before posting here but it didn't work :S – Nik Jun 10 '12 at 20:19
  • Try just -keep instead of -keepnames – Zaid Daghestani Jun 10 '12 at 20:54
  • Doesn't -keep NOT obfuscate the class? – Nik Jun 11 '12 at 15:03
  • Yes it does. -keepnames is a better option if you only want to not obfuscate class names, but keep will do the same. obfuscate = rename. – Zaid Daghestani Jun 11 '12 at 19:07
  • Does "-keepnames" just keep the name of the class ? Or does it do more? I want to just keep the name. – android developer Oct 16 '18 at 07:17
  • @androiddeveloper `-keep` and `-keepnames` do the same as far as obfuscation is concerned (class names specified in `class_specification` are kept). As stated above, the difference is in the shrinking phase (with `-keepnames`, an unused class name is removed instead of kept). Both of them will however obfuscate class members, except if you add a specification to prevent this: adding e.g. `{*;}` at the end of `class_specification` (to keep all class members). Note that adding `{}` is the same as adding no curly brackets at all. – Aymeric S Nov 25 '19 at 09:24
  • @AymericS So it prevents renaming just the class, and if it seems unused, it will remove it. What would happen if you reach the class via reflection? Or even here it depends how you do it, because the shrinker might not understand that the class is really being used? – android developer Nov 25 '19 at 09:34
  • Link in this answer is not working @ZaidDaghestani – Jawad El Fou Nov 16 '21 at 02:46
45

This keeps classnames intact:

-keepnames class com.somepackage.*
tarkeshwar
  • 4,105
  • 4
  • 29
  • 35
20

Handy tip for everyone who does not want ProGuard to change any class name:

# please KEEP ALL THE NAMES
-keepnames class ** { *; }

This way you will get readable stack traces while still throwing out things you don't need. :-)

mreichelt
  • 12,359
  • 6
  • 56
  • 70
5

If anyone is interested how to specify multiple class names to keep, then these classes can be separated by a comma. Example:

-keepnames class com.foo.**,com.bar.** { *; }

It is also possible to use negation with this because usually only own classes would be obfuscated and 3rd party libraries can be kept:

-keepnames class !com.foo.**,!com.bar.** { *; }

See the Proguard Documentation for this.

k_o_
  • 5,143
  • 1
  • 34
  • 43