Fix: 'Invalid heap size' or 'Could not reserve enough space'

Watch the video:

0:00 - Explanation
0:46 - The error
1:30 - Uninstalling Java completely
2:48 - Downloading and installing correct Java
4:00 - Testing

“Invalid maximum heap size”? “Could not reserve enough space”?
There’s a really simple fix. This video shows you how to do it.
Download Java: https://java.com/en/download/manual.jsp