How to return a list of keys from a Hash Map?
Solution 1:
Use the keySet() method to return a set with all the keys of a Map.
If you want to keep your Map ordered you can use a TreeMap.
Solution 2:
Using map.keySet(), you can get a set of keys. Then convert this set into List by:
List<String> l = new ArrayList<String>(map.keySet());
And then use l.get(int) method to access keys.
PS:- source- Most concise way to convert a Set<String> to a List<String>