java - Sort HashMap keys and store in ArrayList -

i need task of sorting hashmap keys string , store them in arraylist. have written below piece of code

public static list<string> getsortedlistbykeys(hashmap<string,string> keysdictionary)     {                 list<string> sortedkeyslist = null;         sortedset<string> sortedkeysset = null;          if(keysdictionary == null || keysdictionary.size() == 0){             return null;         }          sortedkeysset = new treeset<>(keysdictionary.keyset());         sortedkeyslist = new arraylist<>(sortedkeysset);          return sortedkeyslist;     } 

i have run , working fine.

just want know if there better way achieve same

since want sort strings based on natural ordering itself, directly create list , use collections.sort() on it.

sortedkeyslist = new arraylist<>(keysdictionary.keyset()); collections.sort(sortedkeyslist); 

this way can avoid using sortedset intermediate step.