.NET#
Better use windows for this. ilSPY is a little too unstable
Dotpeek (Windows)#
https://www.jetbrains.com/decompiler/
Java#
FernFlower#
Tool to decompile java archive. Install guide:
git clone https://github.com/JetBrains/fernflower.git
cd fernflower
./gradlew build
cd build/libsUsage:
mkdir src
java -jar fernflower.jar app.jar src
cd src
jar -xf app.jarJD-GUI ( Windows)#
https://java-decompiler.github.io/ https://www.java.com/en/download/