Not really a question, more like an observation. Typing JAVAC didn't work for me. What did work was typing JAVA in the command prompt.

Answer 1

javac to compile ".java", java to execute your code

Answer 2

Add PATH to "Environment Variables..." on "System Properties" by right clicking on "My Computer"

In my case the path is:

C:\Program Files\Java\jdk1.8.0_112\bin

jdk1.8.0_112 = Java's version