JEB Decompiler 5.22.0.202412102010 mod by CXV

[mongza]

Originally Posted by PermaNull

APK aren't JAR. Unless you do dex2jar and back the other way.

Options are full decompilation/recompile or modifying the java bytecode afaik. Though with dex2jar you could possibly use Recaf's java editor but I recommend v4 if you do it with this way, otherwise apktool -d and modify the bytecode then re-assemble and sign.

If you're looking to patch/modify it another option is Frida too which would allow you to write JS like syntax, you could modify the bytecode to load Frida agent from libs dir of APK when it's started and place all your code there. This is how Oculus Quest apps are cracked.
https://frida.re/

If I wanted to do this without modifying bytecode and could see actual java code via something like JEB, Frida would be my preferred approach due to the ease-of-use vs trying to manipulate the software via bytecode.

Please re-read Mendax47's question.