Oracle Oracle Certifications 1Z0-819 Questions & Answers

• Question 81:

  Given:

  

  What is required to make the Foo class thread safe?

  A. No change is required.

  B. Make the declaration of lock static.

  C. Replace the lock constructor call with new ReentrantLock (true).

  D. Move the declaration of lock inside the foo method.

  Correct Answer: C

  Reference: https://stackoverflow.com/

• Question 82:

  Given: After which line can we insert assert i < 0 || values[i] <= values[i + 1]; to verify that the values array is partially sorted?

  

  A. after line 8

  B. after line 6

  C. after line 5

  D. after line 10

  Correct Answer: B

  

• Question 83:

  Analyze the code:

  

  Which two options can you insert inside println method to produce Global:namescope? (Choose two.)

  A. Test.prefix+Test.name

  B. new Test().prefix+new Test().name

  C. Test.prefix+Test.getName()

  D. Test.getName+prefix

  E. prefix+Test.name

  F. prefix+name

  Correct Answer: BC

• Question 84:

  Given:

  

  What is the result?

  A. The compilation fails at line 9.

  B. The compilation fails at line 2.

  C. Hello World

  D. The compilation fails at line 8.

  Correct Answer: C

• Question 85:

  

  Which two describe reasons to modularize the JDK? (Choose two.)

  A. easier to understand the Java language

  B. improves security and maintainability

  C. easier to expose implementation details

  D. improves application robustness

  E. easier to build a custom runtime linking application modules and JDK modules

  Correct Answer: BD

• Question 86:

  Which command line runs the main class com.acme.Main from the module com.example?

  A. java --module-path mods com.example/com.acme.Main

  B. java lasspath com.example.jar com.acme.Main

  C. java --module-path mods -m com.example/com.acme.Main

  D. java -classpath com.example.jar com.example/com.acme.Main

  Correct Answer: D

• Question 87:

  Given the declaration:

  

  Examine this code fragment:

  /* Loc1 */ class ProcessOrders { ... }

  Which two annotations may be applied at Loc1 in the code fragment? (Choose two.)

  A. @Resource({"Customer1", "Customer2"})

  B. @Resource(value={{}})

  C. @Resource

  D. @Resource("Customer1")

  E. @Resource()

  Correct Answer: AD

• Question 88:

  Given:

  List list1 = new ArrayList<>();

  list1.add("A");

  list1.add("B");

  List list2 = List.copyOf(list1);

  list2.add("C");

  List> list3 = List.of(list1, list2);

  System.out.println(list3);

  What is the result?

  A. [[A, B],[A, B]]

  B. An exception is thrown at run time.

  C. [[A, B], [A, B, C]]

  D. [[A, B, C], [A, B, C]]

  Correct Answer: B

• Question 89:

  

  Which method throws an exception for not-a-number and infinite input values?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: A

• Question 90:

  Given:

  

  You want to implement the java.io.Serializable interface to the MyPersistenceData class. Which method should be overridden?

  A. the readExternal method

  B. nothing

  C. the readExternal and writeExternal method

  D. the writeExternal method

  Correct Answer: B

  To implement the java.io.Serializable interface to the MyPersistenceData class, you don't need to override any methods. The Serializable interface is a marker interface that doesn't have any methods. It simply indicates that the class is serializable and its objects can be written to and read from a stream. Therefore, the correct answer is B.