How Many Questions Of 1Z0-819 Study Guide

NEW QUESTION 1
Given:

Which one is correct?

• A. An IllegalThreadStateException is thrown at run time.
• B. Three threads are created.
• C. The compilation fails.
• D. Four threads are created.

Answer: A

Explanation:

NEW QUESTION 2
Which interface in the java.util.function package can return a primitive type?

• A. ToDoubleFunction
• B. Supplier
• C. BiFunction
• D. LongConsumer

Answer: A

NEW QUESTION 3
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.

Answer: AC

NEW QUESTION 4
Given:

and

Which code fragment on line 1 makes the s1 set contain the names of all employees born before January 1, 1989?

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Answer: B

NEW QUESTION 5
Given:

What is the result?

• A. 9
• B. An exception is thrown at runtime.
• C. 3
• D. 6

Answer: D

Explanation:

NEW QUESTION 6
Given:

When is the readObject method called?

• A. before this object is deserialized
• B. after this object is deserialized
• C. before this object Is serialized
• D. The method is never called.
• E. after this object is serialized

Answer: B

NEW QUESTION 7
Given:

Which statement is equivalent to line 1?

• A. double totalSalary = list.stream().map(e > e.getSalary() * ratio).reduce (bo).ifPresent (p > p.doubleValue());
• B. double totalSalary = list.stream().mapToDouble(e > e.getSalary() * ratio).sum;
• C. double totalSalary = list.stream().map(Employee::getSalary * ratio).reduce (bo).orElse(0.0);
• D. double totalSalary = list.stream().mapToDouble(e > e.getSalary() * ratio).reduce(starts, bo);

Answer: C

Explanation:

NEW QUESTION 8
Given:

What is the result?

• A. compilation error
• B. 0 5
• C. 6 13
• D. 5 12

Answer: A

Explanation:

NEW QUESTION 9
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”)};

Answer: C

NEW QUESTION 10
What makes Java dynamic?

• A. At runtime, classes are loaded as needed, and new code modules can be loaded on demand.
• B. The runtime can process machine language sources as well as executables from different language compilers.
• C. The Java compiler uses reflection to test if class methods are supported by resources of a target platform.
• D. The Java compiler preprocesses classes to run on specific target platforms.

Answer: A

NEW QUESTION 11
Given:

Which loop incurs a compile time error?

• A. the loop starting line 11
• B. the loop starting line 7
• C. the loop starting line 14
• D. the loop starting line 3

Answer: C

NEW QUESTION 12
Given:

What is the output?

• A. null
• B. A NoSuchElementException is thrown at run time.
• C. Duke
• D. A NullPointerException is thrown at run time.

Answer: C

Explanation:

NEW QUESTION 13
Given:

Assuming that this code compiles correctly, which three statements are true? (Choose three.)

• A. B cannot be abstract.
• B. B is a subtype of A.
• C. A cannot be abstract.
• D. A cannot be final.
• E. B cannot be final.
• F. A is a subtype of B.

Answer: ABD

NEW QUESTION 14
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.

Answer: B

Explanation:

NEW QUESTION 15
Given:
var fruits = List.of(“apple”, “orange”, “banana”, “lemon”);
You want to examine the first element that contains the character n. Which statement will accomplish this?

• A. String result = fruits.stream().filter(f > f.contains(“n”)).findAny();
• B. fruits.stream().filter(f > f.contains(“n”)).forEachOrdered(System.out::print);
• C. Optional<String> result = fruits.stream().filter(f > f.contains (“n”)).findFirst ();
• D. Optional<String> result = fruits.stream().anyMatch(f > f.contains(“n”));

Answer: B

Explanation:

NEW QUESTION 16
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