Cmd/React Native can't detect my JAVA_HOME environment variables

I'm trying to create a React Native app for Android. I use bash from the command line in Windows 10. I browse to the location of my React Native project and then run "react-native run-android". But then I get an error like this:

$ react-native run-android
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 864 file(s) to forward-jetify. Using 4 workers...
info Starting JS server...
/bin/sh: 1: adb: not found
info Launching emulator...
error Failed to launch emulator. Reason: No emulators found as an output of `emulator -list-avds`.
warn Please launch an emulator manually or connect a device. Otherwise app may fail to launch.
info Installing the app...

ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation.


error Failed to install the app. Make sure you have the Android development environment set up: https://facebook.github.io/react-native/docs/getting-started.html#android-development-environment. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
    at checkExecSyncError (child_process.js:601:13)
    at execFileSync (child_process.js:621:13)
    at runOnAllDevices (/mnt/c/users/lenovo/documents/repositories/upself rn/upself/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:94:39)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)

TL;DR it tells me to set the environment variable for JAVA_HOME. AFAIK.

The problem is I've already set the JAVA_HOME since I installed the Windows 10 in my laptop which was months ago. I use JDK 12 and have developed few native Android app using Android Studio using this same laptop and never have I encountered any missing JAVA_HOME issue.

This is what I've tried to try to solve this issue:

• Run the cmd as administrator

• Set the JAVA_HOME to c:\Program Files\Java\jdk-12.0.2\ and the one in Android Studio default SDK location C:\Users\lenovo\AppData\Local\Android\Sdk. Both dont work.

• Restart my laptop and cmd (done it multiple times but it still doesnt work).

• Put a quotation mark between the path (found this in a stack overflow question).

I've read many questions in stack overflow but none of those works.

So, could anyone help me to solve this problem? Why is it unable to detect the environment path?