We all know that minecraft is a game developed from Java, as it is written in its logo from version 1.12.2, Minecraft Java Edition. That way it is necessary to have Java installed and updated to play the game, if you are having problems with java today I will teach you how to solve this problem.
It's a cool tutorial but you're overlooking something very important: ever since the new launcher became a thing it is no longer required to have Java installed on your computer because Minecraft nowadays ships a copy of the Java runtime themselves. Go to your Minecraft installation folder, and there you'll see something like this: runtime\jre-x32\1.8.0_25.
Even though this is a somewhat outdated version of Java (current is 1.8.0_144 at the time of writing) it's actually recommended to use this for better performance (it's enabled by default).