store the pairs as arrays by all means, but if you are going to be changing the size of the overall array then you should definitely use a java.util.Vector.
In fact I'd use a vector for most arrays other than very simple ones.
Also remember that from java 1.4 you can use the split function to split a string into an array i.e. CSV to array:
String sCSVItems = "1,2,3".split(",");
Hopefully that's helpful