The best way to convert a list, Array, Map, set, and other sets in Java

In Java, we often need to do some conversion to list, array, etc., of course there are many kinds of conversion methods, but which method is both convenient and efficient? Let me introduce you to the best conversion method between sets.convert 1.List to array

list<string> list = new arraylist<string> (), List.add ("China"), List.add ("Switzerland"); List.add ("Italy") ); List.add ("France"); String [] countries = List.toarray (New String[list.size ()));

2.Array Conversion to List

string[] countries = {"China", "Switzerland", "Italy", "France"}; List List = arrays.aslist (countries);

3.Map Conversion to List

list<value> list = new arraylist<value> (Map.values ());

4.Array conversion to set

String [] countries = {"India", "Switzerland", "Italy"};      set<string> set = new Hashset<string> (arrays.aslist (countries)); SYSTEM.OUT.PRINTLN (set);

5.MAP conversion to set

Map<integer, string> sourcemap = Createmap (); set<string> targetset = new hashset<> (Sourcemap.values ());

The best way to convert a list, Array, Map, set, and other sets in Java