Install TestNG in Eclipse

https://www.techbeamers.com/install-testng-in-eclipse-ide/#method3

Appium Studio : IDE for Appium automation : Record and Play back tests

Get installed .Net framework in the windows system

dir %windir%\microsoft.net\framework /ad
cd %windir%\microsoft.net\framework\v4.0.30319
msbuild.exe -version

Vysor - Android control on PC : Enable USB Debugging

https://www.vysor.io/

Selendroid is a test automation framework which drives off the UI of Android native and hybrid applications (apps) and the mobile web.

Native, Hybrid apps : iOS apps will not run on Android and vice versa

https://www.mobiloud.com/blog/native-web-or-hybrid-apps/

Most web apps are written mainly in Javascript
Native apps , same language used in operating system development. 
For ex:  
Swift or Objective-C for iOS apps  - Xcode IDE
Java is used to write native Android apps  - Android Studio IDE
C# for the most part for Windows Phone apps.

Building Cross-Platform Native Apps
     Xamarin, React Native, Titanium, and Google’s Flutter

Hybrid Apps:
You install it like a native app, but it’s actually a web app on the inside.

Robotium: Mobile UI automation tool , alternative to appium

https://www.guru99.com/first-android-testing.html