Could not find tools.jar. Please check code example

Example 1: could not find tools.jar linux

on linux -> you need
1) to install openjdk :
sudo apt-get install openjdk-8-jdk
2) export jdk location : 
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64

Example 2: Could not find tools.jar. Please check that

On my system (Win 10, JRE 1.8.0, Android Studio 3.1.2, Gradle 4.1) there is no 
tools.jar in the JRE directory (C:\Program Files\Java\jre1.8.0_171).

However, I found it in C:\Program Files\Android\Android Studio\jre\lib and 
tried setting JAVA_HOME=C:\Program Files\Android\Android Studio\jre

That works (for me)!