How to convert a Navigablemap to String[][]

I need to convert a navigable map to a 2D String array. Below given is a code from an answer to one of my previous question.

NavigableMap<Integer,String> map =
        new TreeMap<Integer, String>();

map.put(0, "Kids");
map.put(11, "Teens");
map.put(20, "Twenties");
map.put(30, "Thirties");
map.put(40, "Forties");
map.put(50, "Senior");
map.put(100, "OMG OMG OMG!");

System.out.println(map.get(map.floorKey(13)));     // Teens
System.out.println(map.get(map.floorKey(29)));     // Twenties
System.out.println(map.get(map.floorKey(30)));     // Thirties
System.out.println(map.floorEntry(42).getValue()); // Forties
System.out.println(map.get(map.floorKey(666)));    // OMG OMG OMG!

I have to convert this map to a 2D String array:

{
{"0-11","Kids"},
{"11-20","Teens"},
{"20-30","Twenties"}
...
}

Is there a fast and elegant way to do this?

Best bet is just to iterate through the Map and create an array for each entry, the troublesome part is generating things like "0-11" since this requires looking for the next highest key...but since the Map is sorted (because you're using a TreeMap) it's no big deal.

String[][] strArr = new String[map.size()][2];
int i = 0;
for(Entry<Integer, String> entry : map.entrySet()){
    // current key
    Integer key = entry.getKey();
    // next key, or null if there isn't one
    Integer nextKey = map.higherKey(key);

    // you might want to define some behavior for when nextKey is null

    // build the "0-11" part (column 0)
    strArr[i][0] = key + "-" + nextKey;

    // add the "Teens" part (this is just the value from the Map Entry)
    strArr[i][1] = entry.getValue();

    // increment i for the next row in strArr
    i++;
}