New to Java

So I have a graph of a bunch of cities connected to other cities. The connections between each city are identified by an integer which would be the price to fly from the source city to the destination. I think using an adjacency matrix would be the best to represent this. I read up on an adjacency matrix and it seems to look exactly like a 2d Array. I wanted to know how this would be implemented, because if I did make a 2d array, how would I get the value of array[san francisco][los angeles]? If there is any confusion as to what I said, please let me know. Thank you, much appreciated.