very cool. termux has to be peak for unbridled nerddom, the new linux terminal in android 16 is really a pale shadow of it. you don't get access to anything non-virtual, not even the gpu (atleast, i couldn't get it to work.) theres so much cool hardware on modern smartphones, with quite solid drivers by virtue of the (relatively stringent) android quality requirements, and its all locked away. video encoders, decoder…
It is possible to write native code for Android using Native Development Kit. Typical NDK use would be to develop a library that is then called into by java code. But one can make whole app with it, 100% java-free: https://github.com/cnlohr/rawdrawandroid
Also NDK is designed to produce shared libraries that are then loaded into the Java host process for the application, if not manually written, one gets the generic activity (NativeActivity or GameActivity) written by the Android team, expecting specific symbols on the shared library mapping to the native method declarations.
https://developer.android.com/reference/android/app/NativeAc...
https://developer.android.com/games/agdk/game-activity
So while someone's own APK might be Java free, there will be Java on the process execution runtime.