Java Multithreading Objective Questions and Answers

Test your skills in Java multithreading with carefully curated objective questions including output-based MCQs. Ideal for interview preparation and mastering concurrency concepts such as synchronization, executors, locks, atomic variables, deadlocks, and performance tuning.

Practice Java Multithreading MCQs with Detailed Explanations

Answer at least 12 questions to submit.

1

Which statement about Thread.start() is correct?

Easy
2

What is the effect of calling Thread.sleep(0)?

Medium
3

Which of the following guarantees visibility across threads without locking?

Medium
4

What happens if wait() is called without owning the object's monitor?

Medium
5

Which ExecutorService is best suited for short-lived asynchronous tasks?

Medium
6

Which situation can cause a deadlock?

Medium
7

Which class provides atomic operations without synchronization?

Medium
8

What is the main benefit of using LongAdder over AtomicLong?

High
9

What state is a thread in after calling wait()?

Medium
10

Which method ensures all previously submitted tasks are completed before returning?

Medium
11

Which is true about synchronized blocks?

Medium
12

What does ThreadLocal provide?

Medium
13

Which is NOT a benefit of using Executors?

Medium
14

What happens if a thread throws an unchecked exception?

Medium
15

Which mechanism supports fairness in locking?

High