Android Studio Private method becomes public final after compile

Question

Using android studio AGP 7.0, Java 11 and minifyEnabled=true

following is my method

private void init(){
}

after compile this becomes public final init() due to which I am getting run time crash saying LinkageError how come access specifier is getting change after compile?

this is not a valid method definition in java – Sergio Feb 21 '22 at 15:27 — Sergio, Feb 21 '22 at 15:27
can you share the whole crash stack? – penkzhou Mar 02 '22 at 13:20 — penkzhou, Mar 02 '22 at 13:20

score 1 · Answer 1 · answered Mar 02 '22 at 13:17

R8 does whole program optimization, and if the method does not have a keep rule R8 can do whatever it wants with the method including changing modifiers. If you want to make sure the method stays you can add a keep rule like this:

-keep class <class name holding method> {
  private void init();
}

then the method should not be touched by R8.

Is the LinkageError caused by adding code at runtime which is not processed by R8? For whole program optimization and boundaries to code not known to R8 must be covered by a keep rule.

Android Studio Private method becomes public final after compile

1 Answers1