Online 1Z0-830 Practice Test

Question 1

Which three of the following are correct about the Java module system?

Options :

A : Code in an explicitly named module can access types in the unnamed module.

B : The unnamed module exports all of its packages.

C :

If a package is defined in both a named module and the unnamed module, then the package in the unnamed module is ignored.

D :

We must add a module descriptor to make an application developed using a Java version prior to SE9 run on Java 11.

E : The unnamed module can only access packages defined in the unnamed module.

F :

If a request is made to load a type whose package is not defined in any known module, then the module system will attempt to load it from the classpath.

Answer: B,C,F

Question 2

Which StringBuilder variable fails to compile? java public class StringBuilderInstantiations { public static void main(String[] args) { var stringBuilder1 = new StringBuilder(); var stringBuilder2 = new StringBuilder(10); var stringBuilder3 = new StringBuilder("Java"); var stringBuilder4 = new StringBuilder(new char[]{'J', 'a', 'v', 'a'}); } }

Options :

A : None of them

B : stringBuilder4

C : stringBuilder1

D : stringBuilder3

E : stringBuilder2

Answer: B

Question 3

Given: java double amount = 42_000.00; NumberFormat format = NumberFormat.getCompactNumberInstance(Locale.FRANCE, NumberFormat.Style. SHORT); System.out.println(format.format(amount)); What is the output?

Options :

A : 42000E

B : 42 000,00 €

C : 42000

D : 42 k

Answer: D

Question 4

Given: java

String bread = optionalName.orElse("Baguette"); System.out.print("bread:" + bread); String dish = optionalName.orElseGet(() -> "Frog legs"); System.out.print(", dish:" + dish); try { String cheese = optionalName.orElseThrow(() -> new Exception()); System.out.println(", cheese:" + cheese); } catch (Exception exc) { System.out.println(", no cheese."); } What is printed?

Options :

A : bread:Baguette, dish:Frog legs, cheese.

B : bread:Baguette, dish:Frog legs, no cheese.

C : bread:bread, dish:dish, cheese.

D : Compilation fails.

Answer: B

Question 5

Which methods compile?

Options :

A :