Higher Test Marks with Free Online 1Z0-830 Exam Practice

Assess the CertsIQ’s updated 1Z0-830 exam questions for free online practice of your Java SE 21 Developer Professional test. Our 1Z0 830 dumps questions will enhance your chances of passing the Oracle Java certification exam with higher marks.

Exam Code: 1Z0-830
Exam Questions: 84
Java SE 21 Developer Professional
Updated: 04 Jun, 2025
Question 1

Which methods compile? 

Options :
Answer: A,B

Question 2

Given: java public class Test { public static void main(String[] args) throws IOException { Path p1 = Path.of("f1.txt"); Path p2 = Path.of("f2.txt"); Files.move(p1, p2); Files.delete(p1); } } In which case does the given program throw an exception?

Options :
Answer: C

Question 3

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 :
Answer: B

Question 4

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 :
Answer: D

Question 5

Given: java ExecutorService service = Executors.newFixedThreadPool(2); Runnable task = () -> System.out.println("Task is complete"); service.submit(task); service.shutdown(); service.submit(task); What happens when executing the given code fragment? 

Options :
Answer: A

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