// "Replace with collect" "true" import java.util.HashMap; import java.util.Map; public class Main { private Map<String, Integer> test(String... list) { HashMap<String, Integer> map = new HashMap<>(); for(String s : lis<caret>t) { if(s != null) { map.put(s, 1); } } return map; } public static void main(String[] args) { System.out.println(new Main().test("a", "bbb", null, "cc", "dd", "eedasfasdfs", "dd")); } }