Oracle Oracle Certifications 1Z0-816 Questions & Answers

• Question 21:

  Given: When run and all three files exist, what is the state of each reader on Line 1?

  

  A. All three readers are still open.

  B. All three readers have been closed.

  C. The compilation fails.

  D. Only reader1 has been closed.

  Correct Answer: C

• Question 22:

  Given the code fragment:

  var pool = Executors.newFixedThreadPool(5);

  Future outcome = pool.submit(() -> 1);

  Which type of lambda expression is passed into submit()?

  A. java.lang.Runnable

  B. java.util.function.Predicate

  C. java.util.function.Function

  D. java.util.concurrent.Callable

  Correct Answer: D

  Reference: https://www.codota.com/code/java/methods/java.util.concurrent.Executors/ newFixedThreadPool

• Question 23:

  Which two statements set the default locale used for formatting numbers, currency, and percentages? (Choose two.)

  A. Locale.setDefault(Locale.Category.FORMAT, "zh-CN");

  B. Locale.setDefault(Locale.Category.FORMAT, Locale.CANADA_FRENCH);

  C. Locale.setDefault(Locale.SIMPLIFIED_CHINESE);

  D. Locale.setDefault("en_CA");

  E. Locale.setDefault("es", Locale.US);

  Correct Answer: BD

  Reference: https://www.oracle.com/technical-resources/articles/javase/locale.html

• Question 24:

  Given:

  

  Which two are secure serialization of these objects? (Choose two.)

  A. Define the serialPersistentFields array field.

  B. Declare fields transient.

  C. Implement only readResolve to replace the instance with a serial proxy and not writeReplace.

  D. Make the class abstract.

  E. Implement only writeReplace to replace the instance with a serial proxy and not readResolve.

  Correct Answer: AC

• Question 25:

  A bookstore's sales are represented by a list of Sale objects populated with the name of the customer and

  the books they purchased.

  public class Sale {

  private String customer;

  private List items;

  // constructor, setters and getters not shown

  }

  public class Book {

  private String name;

  private double price;

  // constructor, setters and getters not shown

  }

  Given a list of Sale objects, tList, which code fragment creates a list of total sales for each customer in

  ascending order?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: C

• Question 26:

  Given:

  

  Which two are correct? (Choose two.)

  A. The output will be exactly 2 1 3 4 5.

  B. The program prints 1 4 2 3, but the order is unpredictable.

  C. Replacing forEach() with forEachOrdered(), the program prints 2 1 3 4 5, but the order is unpredictable.

  D. Replacing forEach() with forEachOrdered(), the program prints 1 2 3 4 5.

  E. Replacing forEach() with forEachOrdered(), the program prints 2 1 3 4 5.

  Correct Answer: BD

• Question 27:

  

  Given the contents:

  MessageBundle.properties file:

  message=Hello

  MessageBundle_en.properties file:

  message=Hello (en)

  MessageBundle_US.properties file:

  message=Hello (US)

  MessageBundle_en_US.properties file:

  message=Hello (en_US)

  MessageBundle_fr_FR.properties file:

  message=Bonjour

  and the code fragment:

  Locale.setDefault(Locale.FRANCE);

  Locale currentLocale = new Locale.Builder().setLanguage("en").build();

  ResourceBundle messages = ResourceBundle.getBundle("MessageBundle", currentLocale);

  System.out. println(messages.getString("message"));

  Which file will display the content on executing the code fragment?

  A. MessageBundle_en_US.properties

  B. MessageBundle_en.properties

  C. MessageBundle_fr_FR.properties

  D. MessageBundle_US.properties

  E. MessageBundle.properties

  Correct Answer: C

  Reference: https://www.javatpoint.com/ResourceBundle-class

• Question 28:

  Given:

  

  And the command: java Main Helloworld What is the result ?

  A. Input: Echo:

  B. Input: Helloworld Echo: Helloworld

  C. Input: Then block until any input comes from System.in.

  D. Input: Echo: Helloworld

  E. A NullPointerException is thrown at run time.

  Correct Answer: C

• Question 29:

  

  Given:

  public class X { }

  and public final class Y extends X { }

  What is the result of compiling these two classes?

  A. The compilation fails because there is no zero args constructor defined in class X.

  B. The compilation fails because either class X or class Y needs to implement the toString() method.

  C. The compilation fails because a final class cannot extend another class.

  D. The compilation succeeds.

  Correct Answer: B

• Question 30:

  

  Which code is correct?

  A. Runnable r = "Message" -> System.out.println();

  B. Runnable r = () -> System.out::print;

  C. Runnable r = () -> {System.out.println("Message");};

  D. Runnable r = -> System.out.println("Message");

  E. Runnable r = {System.out.println("Message")};

  Correct Answer: C

  Reference: https://www.oracle.com/technical-resources/articles/java/architect-lambdas-part1.html