Install Java Compiler

I. Java SE Development Kit 8 Downloads:

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

Note: Java Platform (JDK) 10:  http://www.oracle.com/technetwork/java/javase/downloads/index.html

Accept License Agreement first.

Decide to download either Windows x86 (32-bit PC) or Windows x64 (64-bit PC).

Save the exe file and run it.

II. Set the PATH to your compiler folder:

1. Search the path of the file, java.exe.

2. Right-click on the icon, Computer and click Properties.

3. Click Advanced system setting.

4. Click Environment Variables...

5. Add your path in for the folder of the file, java.exe.

6. Add a new environment variable as below.
The default value of the class path is ".", meaning that only the current directory is searched.