Java large datastructure for storing a matrix

Question

I need to store a 2d matrix containing zip codes and the distance in km between each one of them. My client has an application that calculates the distances which are then s

Answer 1

Create a new class with 2 slots for location names. Have it always put the alphabetically first name in the first slot. Give it a proper equals and hashcode method. Give it a compareTo (e.g. order alphabetically by names). Throw them all in an array. Sort it.

Also, hash1 = hash2 does not imply object1 = object2. Don't ever do this. It's a hack.