1z0-809 Java SE 8 Programmer II Questions and Answers

Given the code fragment:

public class FileThread implements Runnable {

String fName;

public FileThread(String fName) { this.fName = fName; }

public void run () System.out.println(fName);}

public static void main (String[] args) throws IOException, InterruptedException {

ExecutorService executor = Executors.newCachedThreadPool();

Stream listOfFiles = Files.walk(Paths.get(“Java Projects”));

listOfFiles.forEach(line -> {

executor.execute(new FileThread(line.getFileName().toString())); //

line n1

});

executor.shutdown();

executor.awaitTermination(5, TimeUnit.DAYS);//

line n2

}

}

The Java Projects directory exists and contains a list of files.

What is the result?

Given the code fragment:

List list1 = Arrays.asList(10, 20);

List list2 = Arrays.asList(15, 30);

//line n1

Which code fragment, when inserted at line n1, prints 10 20 15 30?

Which two reasons should you use interfaces instead of abstract classes? (Choose two.)

Given the code fragment:

List empDetails = Arrays.asList(“100, Robin, HR”,

“200, Mary, AdminServices”,

“101, Peter, HR”);

empDetails.stream()

.filter(s-> s.contains(“1”))

.sorted()

.forEach(System.out::println); //line n1

What is the result?

Given the code fragment:

List values = Arrays.asList (1, 2, 3);

values.stream ()

.map(n -> n*2)//line n1

.peek(System.out::print)//line n2

.count();

What is the result?

Given:

Book.java:

public class Book {

private String read(String bname) { return “Read” + bname }

}

EBook.java:

public class EBook extends Book {

public class String read (String url) { return “View” + url }

}

Test.java:

public class Test {

public static void main (String[] args) {

Book b1 = new Book();

b1.read(“Java Programing”);

Book b2 = new EBook();

b2.read(“http://ebook.com/ebook”);

}

}

What is the result?

Given that these files exist and are accessible:

and given the code fragment:

Which code fragment can be inserted at line n1 to enable the code to print only /company/emp?

Given the code fragment:

public void recDelete (String dirName) throws IOException {

File [ ] listOfFiles = new File (dirName) .listFiles();

if (listOfFiles ! = null && listOfFiles.length >0) {

for (File aFile : listOfFiles) {

if (!aFile.isDirectory ()) {

if (aFile.getName ().endsWith (“.class”))

aFile.delete ();

}

}

}

}

Assume that Projects contains subdirectories that contain .class files and is passed as an argument to the recDelete () method when it is invoked.

What is the result?

Given the code fragment:

class CallerThread implements Callable {

String str;

public CallerThread(String s) {this.str=s;}

public String call() throws Exception {

return str.concat(“Call”);

}

}

and

public static void main (String[] args) throws InterruptedException, ExecutionException

{

ExecutorService es = Executors.newFixedThreadPool(4); //line n1

Future f1 = es.submit (newCallerThread(“Call”));

String str = f1.get().toString();

System.out.println(str);

}

Which statement is true?

Given the code fragment:

What is the result?

Given:

and the code fragment:

The threads t1 and t2 execute asynchronously and possibly prints ABCA or AACB.

You have been asked to modify the code to make the threads execute synchronously and prints ABC.

Which modification meets the requirement?

Given:

class Sum extends RecursiveAction { //line n1

static final int THRESHOLD_SIZE = 3;

int stIndex, lstIndex;

int [ ] data;

public Sum (int [ ]data, int start, int end) {

this.data = data;

this stIndex = start;

this. lstIndex = end;

}

protected void compute ( ) {

int sum = 0;

if (lstIndex – stIndex <= THRESHOLD_SIZE) {

for (int i = stIndex; i < lstIndex; i++) {

sum += data [i];

}

System.out.println(sum);

} else {

new Sum (data, stIndex + THRESHOLD_SIZE, lstIndex).fork( );

new Sum (data, stIndex,

Math.min (lstIndex, stIndex + THRESHOLD_SIZE)

).compute ();

}

}

}

and the code fragment:

ForkJoinPool fjPool = new ForkJoinPool ( );

int data [ ] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

fjPool.invoke (new Sum (data, 0, data.length));

and given that the sum of all integers from 1 to 10 is 55.

Which statement is true?

Given the code fragment:

BiFunction val = (t1, t2) -> t1 + t2;//line n1

System.out.println(val.apply(10, 10.5));

What is the result?

Given the code fragment:

Which code fragment, when inserted at line n1, ensures false is printed?

Given:

class FuelNotAvailException extends Exception { }

class Vehicle {

void ride() throws FuelNotAvailException {//line n1

System.out.println(“Happy Journey!”);

}

}

class SolarVehicle extends Vehicle {

public void ride () throws FuelNotAvailException {//line n2

super ride ();

}

}

and the code fragment:

public static void main (String[] args) throws Exception {

Vehicle v = new SolarVehicle ();

v.ride();

}

Which modification enables the code fragment to print Happy Journey!?

Given the code fragment:

List nL = Arrays.asList(“Jim”, “John”, “Jeff”);

Function funVal = s -> “Hello : “.concat(s);

nL.Stream()

.map(funVal)

.forEach(s-> System.out.print (s));

What is the result?

Given the code fragment:

List colors = Arrays.asList(“red”, “green”, “yellow”);

Predicate test = n - > {

System.out.println(“Searching…”);

return n.contains(“red”);

};

colors.stream()

.filter(c -> c.length() >= 3)

.allMatch(test);

What is the result?

Given the structure of the Student table:

Student (id INTEGER, name VARCHAR)

Given the records from the STUDENT table:

Given the code fragment:

Assume that:

What is the result?

Given the code fragment:

Path file = Paths.get (“courses.txt”);

// line n1

Assume the courses.txt is accessible.

Which code fragment can be inserted at line n1 to enable the code to print the content of the courses.txt file?

Given the code fragment:

What is the result?

Given:

class Student {

String course, name, city;

public Student (String name, String course, String city) {

this.course = course; this.name = name; this.city = city;

}

public String toString() {

return course + “:” + name + “:” + city;

}

public String getCourse() {return course;}

public String getName() {return name;}

public String getCity() {return city;}

and the code fragment:

List stds = Arrays.asList(

new Student (“Jessy”, “Java ME”, “Chicago”),

new Student (“Helen”, “Java EE”, “Houston”),

new Student (“Mark”, “Java ME”, “Chicago”));

stds.stream()

.collect(Collectors.groupingBy(Student::getCourse))

.forEach(src, res) -> System.out.println(res));

What is the result?

Given the code fragment:

Stream files = Files.list(Paths.get(System.getProperty(“user.home”)));

files.forEach (fName -> {//line n1

try {

Path aPath = fName.toAbsolutePath();//line n2

System.out.println(fName + “:”

+ Files.readAttributes(aPath, Basic.File.Attributes.class).creationTime

());

} catch (IOException ex) {

ex.printStackTrace();

});

What is the result?

Given:

interface Doable {

public void doSomething (String s);

}

Which two class definitions compile? (Choose two.)

Given the code fragment:

ZonedDateTime depart = ZonedDateTime.of(2015, 1, 15, 1, 0, 0, 0, ZoneID.of(“UTC-7”));

ZonedDateTime arrive = ZonedDateTime.of(2015, 1, 15, 9, 0, 0, 0, ZoneID.of(“UTC-5”));

long hrs = ChronoUnit.HOURS.between(depart, arrive); //line n1

System.out.println(“Travel time is” + hrs + “hours”);

What is the result?

Given:

class FuelNotAvailException extends Exception { }

class Vehicle {

void ride() throws FuelNotAvailException {//line n1

System.out.println(“Happy Journey!”);

}

}

class SolarVehicle extends Vehicle {

public void ride () throws Exception {//line n2

super ride ();

}

}

and the code fragment:

public static void main (String[] args) throws FuelNotAvailException, Exception {

Vehicle v = new SolarVehicle ();

v.ride();

}

Which modification enables the code fragment to print Happy Journey!?

Given the code fragment:

public class Foo {

public static void main (String [ ] args) {

Map unsortMap = new HashMap< > ( );

unsortMap.put (10, “z”);

unsortMap.put (5, “b”);

unsortMap.put (1, “d”);

unsortMap.put (7, “e”);

unsortMap.put (50, “j”);

Map treeMap = new TreeMap (new

Comparator ( ) {

@Override public int compare (Integer o1, Integer o2) {return o2.compareTo

(o2); } } );

treeMap.putAll (unsortMap);

for (Map.Entry entry : treeMap.entrySet () ) {

System.out.print (entry.getValue () + “ “);

}

}

}

What is the result?