Java NIO

Here is a few links related to Java NIO:

The most important advantage that NIO introduces is it is non blocking. It uses the modern OS's non blocking feature, thus doesn't need many threads to help overall system utilization. When blocking IO is used, whenever a thread is doing IO, it will be blocked, it cannot be used to for other tasks, thus in such system, multi-threading is necessary to achieve high throughput.
http://blogs.oracle.com/slc/2009/06/javanio_vs_javaio.html

Here is one comparing the performance of different reads

http://nadeausoftware.com/articles/2008/02/java_tip_how_read_files_quickly