Java swapping large objects to disk automatically

This title is misleading. I the article title is "fully automated large object disk swap manager in java". I thought this would be about something which java did automatically.

Ignoring that, the article is quite interesting. The author is, slowly rediscovering techniques which have been used in maps for years, and if he wants to create lots of smallish objects on a file system, I am not entirely clear why he did not just make them separate files, rather than faking his own file system!