Assessment Test

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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);

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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);

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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());

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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);

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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); } }

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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"));

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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}));

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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;

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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;
}

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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: }

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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: } }

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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));

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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 _________ ();

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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: } } }

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

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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._________________;
}

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17. Which is true if the contents of path1 start with the text Howdy? (Choose two.)

System.out.println(Files.mismatch(path1,path2));

1

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: } } }

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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: } }

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20. When printed, which String gives the same value as this text block?

var pooh = """
"Oh, bother." -Pooh
""".indent(1);
System.out.print(pooh);

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

1

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)));

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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: }

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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));

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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: } }

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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());
}

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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 {}

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

1

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(); }

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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: } }

Use the following assessment test to gauge your current level of skill in Java

Assessment Test

Assessment Test

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());

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; }

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 _________ ();

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

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

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.

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());

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;
}

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 _________ ();

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

17. Which is true if the contents of path1 start with the text Howdy? (Choose two.)

System.out.println(Files.mismatch(path1,path2));

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.

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: }

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());
}