Online 1Z0-809 Practice Test

Question 1

Given the code fragments:

class MyThread implements Runnable {

private static AtomicInteger count = new AtomicInteger (0);

public void run () {

int x = count.incrementAndGet();

System.out.print (x+” “);

}

and

Thread thread1 = new Thread(new MyThread());

Thread thread2 = new Thread(new MyThread());

Thread thread3 = new Thread(new MyThread());

Thread [] ta = {thread1, thread2, thread3};

for (int x= 0; x < 3; x++) {

ta[x].start();

}

Which statement is true?

Options :

A : The program prints 1 2 3 and the order is unpredictable

B : The program prints 1 2 3.

C : The program prints 1 1 1

D : A compilation error occurs.

Answer: A

Question 2

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<Path> 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?

Options :

A : The program throws a runtime exception at line n2.

B : The program prints files names concurrently

C : The program prints files names sequentially.

D : A compilation error occurs at line n1

Answer: B

Question 3

Given:

class UserException extends Exception { }

class AgeOutOfLimitException extends UserException { }

and the code fragment:

class App {

public void doRegister(String name, int age)

throws UserException, AgeOutOfLimitException {

if (name.length () < 6) {

throw new UserException ();

} else if (age >= 60) {

throw new AgeOutOfLimitException ();

} else {

System.out.println(“User is registered.”);

}

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

App t = new App ();

t.doRegister(“Mathew”, 60);

}

What is the result?

Options :

A :

User is registered.

B :

An AgeOutOfLimitException is thrown.

C : A UserException is thrown.

D : A compilation error occurs in the main method.

Answer: B

Question 4

Given:

From what threading problem does the program suffer?

Options :

A : race condition

B : deadlock

C : starvation

D : livelock

Answer: B

Question 5

Given the code fragments:

and

What is the result?

Options :

A : null

B : A compilation error occurs.

C : DogCatMouse

D : [Dog, Cat, Mouse]

Answer: D

EXPERTY DESIGNED 1Z0-809 PRACTICE TEST