I used to think about locality a fair amount back when I programmed in C.

In Java, I have no idea whether or not the fields in a copybook^H^H^H^H^H^H^H^H bean are going to be anywhere near contiguous, or not. Packing and unpacking stuff in a byte array / string gets tedious.

It's a shame low level integration isn't somehow easier in Java, like it is in C#.