Oracle Oracle Certifications 1Z0-819 Questions & Answers

• Question 11:

  Given:

  

  Which two lines can replace line 1 so that the Y class compiles? (Choose two.)

  A. map.forEach((k, v) -> set(v)));

  B. set(map.values());

  C. super.set(List map)

  D. super.set(map.values());

  E. set(map)

  Correct Answer: BD

• Question 12:

  Which code fragment prints 100 random numbers?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: D

  Reference: https://www.javacodegeeks.com/2014/01/java-util-random-in-java-8.html

• Question 13:

  Given:

  

  What code must you insert on Line 1 to enable the code to print Hello world?

  A. Hello.Greeting myG = new Hello.Greeting() myG.sayHi();

  B. Hello myH = new Hello(); Hello.Greeting myG = myH.new Greeting(); myG.sayHi();

  C. Hello myH = new Hello(); Hello.Greeting myG = myH.new Hello.Greeting(); myG.sayHi();

  D. Hello myH = new Hello(); Greeting myG = new Greeting(); myG.sayHi ();

  Correct Answer: B

• Question 14:

  Given this enum declaration:

  

  Examine this code:

  System.out.println(Alphabet.getFirstLetter());

  What code should be written at line 3 to make this code print A?

  A. final String getFirstLetter() { return A.toString(); }

  B. static String getFirstLetter() { return Alphabet.values()[1].toString(); }

  C. static String getFirstLetter() { return A.toString(); }

  D. String getFirstLetter() { return A.toString(); }

  Correct Answer: C

• Question 15:

  Given:

  

  Which two allow a.Main to allocate a new Person? (Choose two.)

  A. In Line 1, change the access modifier to privateprivate Person() {

  B. In Line 1, change the access modifier to publicpublic Person() {

  C. In Line 2, add extends Person to the Main classpublic class Main extends Person {and change Line 3 to create a new Main objectPerson person = new Main();

  D. In Line 2, change the access modifier to protectedprotected class Main {

  E. In Line 1, remove the access modifierPerson() {

  Correct Answer: BC

• Question 16:

  Given:

  

  What is the result?

  A. 3 5 3 3

  B. 3 3 3 3

  C. 3 5 3 5

  D. 5 5 3 3

  Correct Answer: A

  

• Question 17:

  Your organization provides a cloud server to your customer to run their Java code. You are reviewing the changes for the next release and you see this change in one of the config files:

  

  Which is correct?

  A. You accept the change because -noverify is necessary for your code to run with the latest version of Java.

  B. You reject the change because -Xms8g -Xmx8g uses too much system memory.

  C. You accept the change because -noverify is a standard option that has been supported since Java 1.0.

  D. You reject the change because -noverify is a critical security risk.

  Correct Answer: D

• Question 18:

  Given:

  

  and

  

  What is the result?

  A. A NullPointerException is thrown at run time.

  B. The compilation fails.

  C. 1 Null null

  D. 1

  E. A ClassCastException is thrown at run time.

  Correct Answer: B

  

• Question 19:

  Given the content from the course.txt file:

  

  Given the code fragment:

  

  Which code fragment at line 1 prints the lines that contain Java from the course.txt file?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  E. Option E

  Correct Answer: E

• Question 20:

  Which two statements correctly describe capabilities of interfaces and abstract classes? (Choose two.)

  A. Interfaces cannot have protected methods but abstract classes can.

  B. Both interfaces and abstract classes can have final methods.

  C. Interfaces cannot have instance fields but abstract classes can.

  D. Interfaces cannot have static methods but abstract classes can.

  E. Interfaces cannot have methods with bodies but abstract classes can.

  Correct Answer: AC

  Reference: https://www.guru99.com/interface-vs-abstract-class-java.html