That is something Minecraft developers could have done years ago. The binary license of the JRE allows it to be bundled with an application for private use of that application.
When redistributing the JRE on Microsoft Windows as a private application runtime (not accessible by other applications) with a custom launcher, the following files are also optional. These are libraries and executables that are used for Java support in Internet Explorer and Mozilla family browsers; these files are not needed in a private JRE redistribution.
from the Java 8 README