I'm definitely not a knowledgeable Java dude but it seems to be just an mmap()'d file wrapped in a class. I don't understand how this fits the description the author provided. I also don't understand how he can call it an "in memory database" in the first paragraph and then say "can be much larger than your physical memory size (only limited by the size of your disk)". Any Java kids who have digested those couple code files want to help me understand?

i haven't looked at the code, but i have dabbled in some performance coding... if you can stream things in and out quickly, and in operations that themselves take as little as possible memory, then you can operate on very large files in mostly directly linear time with relation to the size of the file... so while the packet in the stream might be in memory at the time your code runs against it, it must seem to be saying that not only can you do that, but we can also stream files through this thing without having to read the file all at once into memory (which works great and fast on very small files, but can downright non functional for large files) .... just a guess... a lot of performance stuff i've been around is a hot-potato situation, so maybe they're trying to describe that.