[kuschku]

From the article:

> JDK 9 downloads are larger than JDK 8 downloads because they include JMOD files so that you can create custom run-time images. To learn about JMOD files see the Project Jigsaw Quick-Start Guide and JEP 282.

[silb]

The javac compiler has a new option "--release" which can compile against previous Java releases 6, 7 and 8. So the new JDK bundles parts of the previous releases.