Java HashSet Cheat sheet

public class SetDemo { public static void main(String[] args) { //Initializing a new HashSet HashSet<String> mySet = new HashSet<>(); //Adding values to set mySet.add("One"); mySet.add("Two"); mySet.add("Two"); mySet.add("Three"); //Printing set System.out.println(mySet); //Adding values in Bulk //Add values from myList to mySet maintaing unique constraints ArrayList<String> myList = new ArrayList<>(); myList.add("Four"); myList.add("Five"); myList.add("Three"); mySet.addAll(myList); System.out.println(mySet); //Accessing values using for-each loop System.out.println("=====for-each========"); for(String element : mySet) { System.out.println(element); } //Accessing values using iterator System.out.println("=====Iterator========"); Iterator<String> it = mySet.iterator(); while(it.hasNext()) { System.out.println(it.next()); } //Accessing values using forEach System.out.println("Using forEach and Consumer========"); mySet.forEach(System.out::println); //Clearing //mySet.clear(); //Check size System.out.println(mySet.size() + ", " + mySet.isEmpty()); //Contains check -- constant time performance System.out.println(mySet.contains("Two")); //Removing elements mySet.remove("Three"); System.out.println(mySet); //Retain elements ArrayList<String> keepThese = new ArrayList<>(); keepThese.add("Four"); keepThese.add("Two"); mySet.retainAll(keepThese); System.out.println(mySet); //Converting set to Array Object[] arr = mySet.toArray(); String[] strArray = mySet.toArray(new String[0]); //Using Stream List<String> fromSet = mySet.stream().collect(Collectors.toList()); System.out.println(fromSet); //---------------------------------------------------------------- //----------------- LinkedHashSet -------------------------------- //---------------------------------------------------------------- //Initializing LinkedHashSet System.out.println("=========LinkedHashSet=========="); LinkedHashSet<String> lSet = new LinkedHashSet<>(); lSet.add("One"); lSet.add("Two"); lSet.add("Four"); lSet.add("Three"); lSet.add("Three"); System.out.println(lSet); for (String element : lSet) { System.out.println(element); } } }