16 Popular & Better Multithreading Interview Questions

Multithreading interview questions are crucial concept, especially for Java developers.

There is a good probability that the interviewer will ask you a question on multithreading whether you are an expert or a beginner. So, brushing up your knowledge of some common interview questions on the subject will prepare you before the interview.

This article lists some popular multithreading questions with example answer for better comprehension.

16 Common Multithreading Interview Questions

Below are some sample multithreading interview questionsand answers to help you prepare for an interview with the prospective employer:

1. What’s a Thread?

Proficiency in multithreading requires a sound knowledge of the instruction threads.

So, this is often a common question by the interviewer to gauge your level of programming knowledge and familiarity with the fundamentals of multithreading. You might demonstrate your comprehension of the topic by providing a brief definition rather than a lengthy or in-depth one.

Sample Answer:Threads are the smallest unit of processing or a distinct execution path that can be managed by a scheduler. A process allows a single thread or multiple threads to run simultaneously using the same resources.

2. What’s Multithreading?

An essential idea in programming is multithreading. The interviewer can determine how well you understand the subject by how well you can briefly describe multithreading. Be sure to make your response concise and specific enough to show that you have the necessary knowledge to answer this issue.

Sample Answer:Multithreading is the capacity of the CPU to execute multiple threads independently and simultaneously. Although they all use the same process resources, each thread still runs on its own.

3. What Is the Key Difference Between a Thread and a Process?

Developers can create numerous threads inside a single process thanks to multithreading. People who are not familiar with multithreading might not be able to distinguish between these two ideas.

An interviewer might test your skills and expertise by asking this question. Briefly define each concept and describe how it relates to the other in your response.

Sample Answer: A process refers to a single program in execution, i.e., an active program. But a thread is the smallest unit or subprocess of that particular program. Each process in memory has a unique address space, but address spaces are shared among threads.

4. What Is a Thread Pool?

A thread pool is a framework used to facilitate the process of multithreading.

The hiring manager may use a question about thread pools to find out if you have experience writing performance-efficient code. Try to give a short but detailed definition in your answer while mentioning the benefits of thread pools.

Sample Answer: A thread pool is a group of worker threads established at the startup. Programmers can use these threads to execute tasks as required and put them back in the pool when the task is completed. The fundamental benefit of a thread pool is that it increases application performance by providing a ready supply of threads when you need them.

5. What States Can a Tread Have During Its Lifetime?

Programmers should be aware of the various states that threads can be in throughout their lifetime.

Understanding the many stages of a thread can demonstrate your understanding of how they work and your ability to troubleshoot a faulty thread. During the interview, the interviewer could quiz you on debugging. When providing your response, list the five possible states a thread can be in.

Sample Answer:A thread can be in five different states during its lifetime: New, Runnable, Running, Waited/Blocked, and Dead/Terminated.

6. What’s a Race Condition?

Race condition happens when a system is unable to carry out several functions at once.

It’s crucial to demonstrate an understanding of the topic because this question deals with one of the main barriers to multithreading. In your response, explain what a race condition is and what approach a programmer might use to resolve the problem.

Sample Answer: A race condition develops when multiple threads compete for priority to run first. Unexpected behavior might be exhibited in the code if the thread that wins the race wasn’t the one that was supposed to run first. Synchronization is the solution to this issue.

7. What’s Synchronization?

Synchronization is an effective process that avoids thread interferences or fixes race conditions that arise during multithreading. If you mentioned synchronization in a different response, the interviewer might ask you to clarify it in more detail.

Understanding synchronization demonstrates your ability to mitigate some of the risks associated with multithreading. In your response, you can briefly explain what synchronization achieves.

Sample Answer: Synchronization enables threads to run one at a time. It avoids a race condition by preventing multiple threads from going after the same task at once.

8. Why Might You Use a Synchronized Block?

A synchronized block is a piece of code that helps to synchronize any specific subset of the function or the method.

This question lets the interviewer know your understanding of multiple threads management. Briefly explain synchronized block and its functionality in the context of multithreading.

Sample Answer: A synchronized block marks a specific portion of a method as synchronized, allowing it to execute only one thread at a time. It means that only one thread can run at a time until it is finished, giving it priority over other threads.

9. What’s a Context Switch?

Context switching is an important concept of multithreading. It allows programmers to store the existing state of a thread so that it can be executed later if needed.

Context switching may be brought up in an interview to test your comprehension of how multithreading functions on the CPU. Explain what a context switch is and why multithreading relies on it in your response to this question.

Sample Answer: Context switching is where the current state of a thread or process is stored to be executed or resumed later when needed. Essentially, context switching refers to switching the CPU from one process or thread to another. This makes it possible for one CPU to control numerous threads or processes.

10. Explain Thread Scheduler and Its Relationship to Thread Priority.

This is another question that deals with the operation of multithreading at the CPU level. Programmers must understand how to write thread scheduling algorithms that prioritize various threads. In your response, give a simple explanation of a thread scheduler’s functionality.

Sample Answer: A thread scheduler determines the order of the thread execution and allocates the CPU time to each thread accordingly.

11. What’s Time Slicing?

Time slicing is another programming concept that has to do with CPU consumption. This question lets the interviewer know that you are familiar with how a thread scheduler operates. Explain the function of time slicing in thread scheduling in your response to this question.

Sample Answer:The thread scheduler uses a process called “time slicing” to distribute CPU time across the available active threads at a given time. A specific thread that expires must wait until other threads in a round-robin method get a chance to use their remaining time. Every running thread will be executed for a set amount of time.

12. What’s Thread Starvation?

Thread starvation is a situation that occurs when a thread runs out of resources and cannot progress.

Thread hunger is a frequent problem that can lead to malfunctions, and understanding this phenomenon can help with code debugging. In your response, define what thread starvation is and explain when it might occur.

Sample Answer: Thread starvation is a condition where a thread cannot be executed due to a limited CPU capacity. This can occur due to low-priority threads that programmers deactivate in favor of other threads. High-priority threads occupy the resources for so long that lower-priority threads cannot access their shared resources to progress.

13. Can You Start a Thread Twice?

Threads go through several states as they progress through their lifecycle. This question demonstrates to interviewers that you are familiar with the fundamental ideas of thread states and lifecycles. Briefly state that you cannot start the same thread twice and explain the reasons.

Sample Answer:Once you start executing a thread, it’s dead, and you can never restart it. If you try to restart the thread, it will throw an exception.

14. What’s a Daemon Thread?

A daemon is a specific type of support thread that carries out unique tasks. It is likely that you use daemon threads as a programmer, and interviewers will test your knowledge of them.

When answering this question, make sure to define a daemon thread and explain what it does and how it is related to conventional threads.

Sample Answer:A daemon thread is a low-priority thread that runs in the background to provide support to other functional threads. When these threads expire, the daemon threads terminate on their own.

15. Can You Describe a Deadlock Situation?

Deadlock is a common situation that causes a code to stall because two threads become blocked forever.

Your ability to articulate the issue shows that you are aware of the problem and might know how to resolve it. In your response, make sure to define a deadlock situation and list the potential causes for one.

Sample Answer: A deadlock scenario develops when multiple threads are waiting for the release of CPU resources to run. For instance, this might occur when one thread has exclusive priority but needs resources from another that is waiting. The situation could also arise when all of the threads are reliant on one another to release the resources necessary.

16. How Do You Create a Thread in Java?

Creating a thread is one of the most fundamental tasks you could encounter as a programmer.

Your ability to answer this question indicates your Java knowledge and fundamental coding skills. When responding, make an effort to offer more than one way to showcase your knowledge.

Sample Answer: In Java, we can create a thread in two ways. We can either create a class that extends the thread class or implement the Runnable interface on a class and create a thread object.


In this article, we’ve taken a look at 16 popular and better multithreading interview questions. If you’re preparing for interviews for programming, feel free to brush up on your knowledge of these classic multithreading interview questions.

We often dive deep into complex theories so much that the basic ones get left out. So, make sure to review the questions in this post before your upcoming interview for a Java developer position.

Abir is a data analyst and researcher. Among her interests are artificial intelligence, machine learning, and natural language processing. As a humanitarian and educator, she actively supports women in tech and promotes diversity.

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