best practice for processing large binary file

[Andrew M]

> For JDK7 I don't know if there's a better / new way but I would
> use MappedByteBuffer for such cases:
> http://download.oracle.com/javase/7/docs/api/java/nio/MappedByteBuffer.html

Should I still have a thread reading the file's records into a queue 
while another consumer thread consumes the byte arrays from the queue? 
Or is it now just as good for me to have just a single thread calling 
myMappedByteBuffer.getFloat or getInt, etc since the myMappedByteBuffer 
is reading the file in another thread?

What if the file being read is larger than available heap?

Thanks!
Andrew