How to execute running Java code directly on Android (without | Android Security & Malware

How to execute running Java code directly on Android (without creating an APK)
Part 1: https://raccoon.onyxbits.de/blog/run-java-app-android/
Part 2: https://raccoon.onyxbits.de/blog/programmatically-talking-to-the-android-system-adb-shell/