|
| 1 | +import java.util.ArrayList; |
| 2 | +import java.util.Collection; |
| 3 | +import java.util.List; |
| 4 | +import java.util.Set; |
| 5 | +import java.util.stream.Collectors; |
| 6 | + |
| 7 | +/** |
| 8 | + * In this challenge we have: |
| 9 | + * + when creating collection using the of method, we create immutable collection, so |
| 10 | + * for example: List<String> list = List.of(); we can't modify the list. |
| 11 | + * as a result an exception is thrown. |
| 12 | + * |
| 13 | + * + Set.of() and Set.copyOf() return an unmodifiable Set. |
| 14 | + * Set.of("Joker","Riddler","Joker") will throw an exception as the arguments contains duplicate elements. |
| 15 | + */ |
| 16 | +public class Challenge_5{ |
| 17 | + |
| 18 | + public static void main( String[] args ) { |
| 19 | + final Collection<Object> finalDcCharacters = new ArrayList<>(); |
| 20 | + List<String> list = List.of(); //empty list |
| 21 | + Set<Object> set = Set.of(); //empty set |
| 22 | + |
| 23 | + try { |
| 24 | + list.add("Deadpool"); // all mutating methods throw UnsupportedOperationException |
| 25 | + }catch (UnsupportedOperationException e){ |
| 26 | + System.out.println("no space fro Marvel hero here"); |
| 27 | + } |
| 28 | + |
| 29 | + try { |
| 30 | + final List<Object> objects = set.stream().collect(Collectors.toList()); |
| 31 | + boolean added = objects.add("Harley Quinn"); |
| 32 | + System.out.println("added "+added); |
| 33 | + finalDcCharacters.addAll(new ArrayList<>(set)); |
| 34 | + }catch (UnsupportedOperationException | IllegalArgumentException e){ |
| 35 | + System.out.print("no space for villains"); |
| 36 | + System.exit(0); |
| 37 | + } |
| 38 | + try { |
| 39 | + var villains = Set.copyOf(set);//this method return an unmodifiable Set |
| 40 | + finalDcCharacters.addAll(List.of(villains, Set.of("Joker","Riddler","Joker"))); |
| 41 | + }catch (IllegalArgumentException e){ |
| 42 | + System.out.println("Where are the villains?"); |
| 43 | + } |
| 44 | + finalDcCharacters.forEach(System.out::println); |
| 45 | + } |
| 46 | +} |
0 commit comments