Best data structure for this problem?

Question

I am using Java for this program, and I currently have a situation where I want to add key/value pairs to a table with integer keys, like

add (1, "Bobby")
add (6, "Sue")
add (3, "Mary")
add (8, "John")
add (15, "Joe")

So naturally I want to do something like a hashtable, but when I do a lookup, if it doesn't find the exact value, I would like it to return the nearest key that isn't greater than the requested key.

So for example, if I lookup 7, it should return "Sue", but if I lookup 9, it should return "John"

I'm hoping to use one of the java util classes (HashTable, TreeMap, etc) but I'm not quite sure how to do it.

Answer 1

NavigableMap would do the trick.