Using keySet() method then changing the Set to a String Array? Java

Question

So this should be really simple since I know it's possible (I just don't understand 'Set' very much).

So basically there is this TreeMap, let's call it aTree. So I need to do something like:

somethingHereProbably = aTree.keySet();
somethingHereProbably.toStringArray();

Solution

You can do

Map<String, Object> map = ...
String[] strings = map.keySet().toArray(new String[map.size()]);

This works for any kind of map, including TreeMap