Assessment Test

1. What is the result of executing the following code snippet? 41: final int score1 = 8, score2 = 3; 42: char myScore = 7; 43: var goal = switch (myScore) { 44: default -> {if(10>score1) yield "unknown";} 45: case score1 -> "great"; 46: case 2, 4, 6 -> "good"; 47: case score2, 0 -> {"bad";} 48: }; 49: System.out.println(goal);

2. What is the output of the following code snippet? int moon = 9, star = 2 + 2 * 3; float sun = star>10 ? 1 : 3; double jupiter = (sun + moon) - 1.0f; int mars = --moon <= 8 ? 2 : 3; System.out.println(sun+", "+jupiter+", "+mars);

3. Which changes, when made independently, guarantee the following code snippet prints 100 at runtime? (Choose all that apply.) List<Integer> data = new ArrayList<>(); IntStream.range(0,100).parallel().forEach(s -> data.add(s)); System.out.println(data.size());

4. What is the output of this code? 20: Predicate<String> empty = String::isEmpty; 21: Predicate<String> notEmpty = empty.negate(); 22: 23: var result = Stream.generate(() -> "") 24: .filter(notEmpty) 25: .collect(Collectors.groupingBy(k -> k)) 26: .entrySet() 27: .stream() 28: .map(Entry::getValue) 29: .flatMap(Collection::stream) 30: .collect(Collectors.partitioningBy(notEmpty)); 31: System.out.println(result);

5. What is the result of the following program? 1: public class MathFunctions { 2: public static void addToInt(int x, int amountToAdd) { 3: x = x + amountToAdd; 4: } 5: public static void main(String[] args) { 6: var a = 15; 7: var b = 10; 8: MathFunctions.addToInt(a, b); 9: System.out.println(a); } }

6. Suppose that we have the following property files and code. What values are printed on lines 8 and 9, respectively? Penguin.properties name=Billy age=1 Penguin_de.properties name=Chilly age=4 Penguin_en.properties name=Willy 5: Locale fr = new Locale("fr"); 6: Locale.setDefault(new Locale("en", "US")); 7: var b = ResourceBundle.getBundle("Penguin", fr); 8: System.out.println(b.getString("name")); 9: System.out.println(b.getString("age"));

7. What is guaranteed to be printed by the following code? (Choose all that apply.) int[] array = {6,9,8}; System.out.println("B" + Arrays.binarySearch(array,9)); System.out.println("C" + Arrays.compare(array, new int[] {6, 9, 8})); System.out.println("M" + Arrays.mismatch(array, new int[] {6, 9, 8}));

8. Which functional interfaces complete the following code, presuming variable r exists? (Choose all that apply.) 6: ______ x = r.negate(); 7: ______ y = () -> System.out.println(); 8: ______ z = (a, b) -> a - b;

9. Suppose you have a module named com.vet. Where could you place the following module-info.java file to create a valid module? public module com.vet { exports com.vet; }

10. What is the output of the following program? (Choose all that apply.) 1: interface HasTail { private int getTailLength(); } 2: abstract class Puma implements HasTail { 3: String getTailLength() { return "4"; } 4: } 5: public class Cougar implements HasTail { 6: public static void main(String[] args) { 7: var puma = new Puma() {}; 8: System.out.println(puma.getTailLength()); 9: } 10: public int getTailLength(int length) { return 2; } 11: }

11. Which lines in Tadpole.java give a compiler error? (Choose all that apply.) // Frog.java 1: package animal; 2: public class Frog { 3: protected void ribbit() { } 4: void jump() { } 5: } // Tadpole.java 1: package other; 2: import animal.*; 3: public class Tadpole extends Frog { 4: public static void main(String[] args) { 5: Tadpole t = new Tadpole(); 6: t.ribbit(); 7: t.jump(); 8: Frog f = new Tadpole(); 9: f.ribbit(); 10: f.jump(); 11: } }

12. Which of the following can fill in the blanks in order to make this code compile? __________ a = __________.getConnection( url, userName, password); __________ b = a.prepareStatement(sql); __________ c = b.executeQuery(); if (c.next()) System.out.println(c.getString(1));

13. Which of the following statements can fill in the blank to make the code compile successfully? (Choose all that apply.) Set<? extends RuntimeException> mySet = new _________ ();

14. Assume that birds.dat exists, is accessible, and contains data for a Bird object. What is the result of executing the following code? (Choose all that apply.) 1: import java.io.*; 2: public class Bird { 3: private String name; 4: private transient Integer age; 5: 6: // Getters/setters omitted 7: 8: public static void main(String[] args) { 9: try(var is = new ObjectInputStream( 10: new BufferedInputStream( 11: new FileInputStream("birds.dat")))) { 12: Bird b = is.readObject(); 13: System.out.println(b.age); 14: } } }

15. Which of the following are valid instance members of a class? (Choose all that apply.)

16. Which is true if the table is empty before this code is run? (Choose all that apply.) var sql = "INSERT INTO people VALUES(?, ?, ?)"; conn.setAutoCommit(false); try (var ps = conn.prepareStatement(sql, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)) { ps.setInt(1, 1); ps.setString(2, "Joslyn"); ps.setString(3, "NY"); ps.executeUpdate(); Savepoint sp = conn.setSavepoint(); ps.setInt(1, 2); ps.setString(2, "Kara"); ps.executeUpdate(); conn._________________; }

17. Which is true if the contents of path1 start with the text Howdy? (Choose two.) System.out.println(Files.mismatch(path1,path2));

18. Which of the following types can be inserted into the blank to allow the program to compile successfully? (Choose all that apply.) 1: import java.util.*; 2: final class Amphibian {} 3: abstract class Tadpole extends Amphibian {} 4: public class FindAllTadpoles { 5: public static void main(String… args) { 6: var tadpoles = new ArrayList<Tadpole>(); 7: for (var amphibian : tadpoles) { 8: ___________ tadpole = amphibian; 9: } } }

19. What is the result of compiling and executing the following program? 1: public class FeedingSchedule { 2: public static void main(String[] args) { 3: var x = 5; 4: var j = 0; 5: OUTER: for (var i = 0; i < 3;) 6: INNER: do { 7: i++; 8: x++; 9: if (x> 10) break INNER; 10: x += 4; 11: j++; 12: } while (j <= 2); 13: System.out.println(x); 14: } }

20. When printed, which String gives the same value as this text block? var pooh = """ "Oh, bother." -Pooh """.indent(1); System.out.print(pooh);

21. A(n) _________________ module always contains a module-info.java file, while a(n) _________________ module always exports all its packages to other modules.

22. What is the result of the following code? 22: var treeMap = new TreeMap<Character, Integer>(); 23: treeMap.put('k', 1); 24: treeMap.put('k', 2); 25: treeMap.put('m', 3); 26: treeMap.put('M', 4); 27: treeMap.replaceAll((k, v) -> v + v); 28: treeMap.keySet() 29: .forEach(k -> System.out.print(treeMap.get(k)));

23. Which of the following lines can fill in the blank to print true? (Choose all that apply.) 10: public static void main(String[] args) { 11: System.out.println(test(____________________________)); 12: } 13: private static boolean test(Function<Integer, Boolean> b) { 14: return b.apply(5); 15: }

24. How many times is the word true printed? var s1 = "Java"; var s2 = "Java"; var s3 = s1.indent(1).strip(); var s4 = s3.intern(); var sb1 = new StringBuilder(); sb1.append("Ja").append("va"); System.out.println(s1 == s2); System.out.println(s1.equals(s2)); System.out.println(s1 == s3); System.out.println(s1 == s4); System.out.println(sb1.toString() == s1); System.out.println(sb1.toString().equals(s1));

25. What is the output of the following program? 1: class Deer { 2: public Deer() {System.out.print("Deer");} 3: public Deer(int age) {System.out.print("DeerAge");} 4: protected boolean hasHorns() { return false; } 5: } 6: public class Reindeer extends Deer { 7: public Reindeer(int age) {System.out.print("Reindeer");} 8: public boolean hasHorns() { return true; } 9: public static void main(String[] args) { 10: Deer deer = new Reindeer(5); 11: System.out.println("," + deer.hasHorns()); 12: } }

26. Which of the following are true? (Choose all that apply.) private static void magic(Stream<Integer> s) { Optional o = s .filter(x -> x < 5) .limit(3) .max((x, y) -> x-y); System.out.println(o.get()); }

27. Assuming the following declarations are top-level types declared in the same file, which successfully compile? (Choose all that apply.) record Music() { final int score = 10; } record Song(String lyrics) { Song { this.lyrics = lyrics + "Hello World"; } } sealed class Dance {} record March() { @Override String toString() { return null; } } class Ballet extends Dance {}

28. Which of the following expressions compile without error? (Choose all that apply.)

29. What is the result of executing the following application? final var cb = new CyclicBarrier(3, () -> System.out.println("Clean!")); // u1 ExecutorService service = Executors.newSingleThreadExecutor(); try { IntStream.generate(() -> 1) .limit(12) .parallel() .forEach(i -> service.submit(() -> cb.await())); // u2 } finally { service.shutdown(); }

30. Which statement about the following method is true? 5: public static void main(String… unused) { 6: System.out.print("a"); 7: try (StringBuilder reader = new StringBuilder()) { 8: System.out.print("b"); 9: throw new IllegalArgumentException(); 10: } catch (Exception e || RuntimeException e) { 11: System.out.print("c"); 12: throw new FileNotFoundException(); 13: } finally { 14: System.out.print("d"); 15: } }