import java.util.HashMap; public class start { public static void main(String args[]) //static method { String[] data = {"1", "2", "3", "4", "5", "2"}; transformList(data); } public static void transformList(String listOfStrings[]) { HashMap<String, Integer> maps = new HashMap<>(); for (int x = 0; x < listOfStrings.length; x++) { if (!maps.containsKey(listOfStrings[x])) { maps.put(listOfStrings[x], x); return; } System.out.println("We have the key hence there is a loop"); } } }