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Top 20 JMeter Interview Questions and Answers

Published On: June 7, 2024

JMeter Interview Questions and Answers

There will be plenty of opportunities for you to advance in your JMeter testing career. The top 20 JMeter interview questions and answers are provided here to help both freshers and experienced professionals demonstrate their skills effectively during interviews.

JMeter Interview Questions and Answers for Freshers

1. Define a thread group in JMeter

The thread number, which acts as virtual users or threads to mimic numerous concurrent users in a performance test, is a crucial part of JMeter.

2. What is performance testing?

The process of evaluating an application’s performance under high demand is known as performance testing. It is nonfunctional testing, typically done before the software is approved for production.

This ensures that the program will work correctly in any scenario and won’t encounter issues such as crashes when it loads. Keeping an eye on performance is an essential duty. 

3. What is JMeter?

It is primarily a Java-based tool for the performance evaluation of applications. Because it is open-source, this is the best choice for this assignment.

This tool makes it simple to finish a range of app performance checks. It doesn’t matter if they are online services or web-based apps.

It also has database and FTP server management capabilities. 

4. How can you send queries to the server using JMeter?

Samplers are employed to assist with this. Many samplers are included in the JMeter, some of which are often used. Among them are: 

  • Junit request
  • JDBC request
  • HTTP request

5. What are the features of JMeter?

Its robustness, portability, and flexibility are some of its primary characteristics. It supports all programs that use Java because it is developed on that platform. Users may be shown the final result in a tabular or graphical format.

JMeter has a playback feature, which makes it possible to write test scripts rapidly. Furthermore, the user need not be concerned about the protocols that this tool may test.

6. What is the process of parameterization?

It is a fairly straightforward technique that parameterizes the various input kinds. This helps the users make use of the unique values.

7. What is your understanding of the correlation?

Essentially, it involves luring in the information from earlier calls and delivering it as parameters to subsequent queries. It greatly facilitates the scripting process and has the advantage of removing a great deal of complexity from the management of sessions.

8. Explain configuration elements.

In JMeter, customizing the queries that samplers frequently make is a crucial responsibility. Configuration elements are used to help accomplish the same task. They are also useful for combining the information from the CSV file with the sampler requests.

9. What specifics regarding a workbench in Jmeter are you aware of?

  • It is frequently felt that test pieces need to be stored when working through the tasks in Jmeter. workbench temporarily keeps them all stored. 
  • There are certain nontest aspects included in it in addition to the testing parts. This program includes a browser that makes it easy to configure these components. 
  • Anything that is kept on the workbench is not genuinely kept in memory forever.

10. Explain the Ramp-up period

When testing an application’s loading, a small number of users are taken into account to analyze the app’s behavior and gather a wealth of useful information about the app’s overall performance. 

Naturally, it takes some time for all of the users to enter the running state; this period is known as the ramp-up time and varies depending on the application, the number of users overall, the amount of data, and many other factors.

JMeter Interview Questions and Answers

11. Give a couple of JMeter timers a name. Why are they taken into consideration?

Several popular timers utilized in JMeter include:

  • Synchronizing timer
  • Uniform random timer
  • Gaussian random timer
  • Constant timer

It is frequently necessary to halt a thread’s test gassing for a set amount of time. Timers serve the same function. They can accurately mimic an actual user’s thought process.

12. What is your knowledge of JMeter’s pre-processors?

Pre-processors are run before completing the sample requests. These are essentially test plans that help guarantee dependability. 

Several of JMeter’s commonly utilized pre-processors include: 

  • RegEx
  • Beanshell
  • Rewriting modifier
  • Link paper for HTML

13. How do you configure a master-slave configuration in JMeter?

One kind of distributed testing is the use of numerous machines to load test a single server in a master-slave setup.

It is imperative that every machine has the same JMeter version and is connected to the same network. One machine is identified as the master and the others as slaves in distributed testing.

The steps are as follows:

  • Add the IP addresses of the slave machines to the remote host column in the JMeter.properties file on the master server.
  • After saving the file, launch JMeter again.
  • Enter the IP address of the system to be invoked and choose Remote Start from JMeter’s RUN menu. 
  • Go to the RUN menu and choose Remote Start to launch all of the slave computers for testing.

14. What is the order of execution of JMeter test plan elements?

The execution order of JMeter’s test plan elements is:

  1. Configuration elements
  2. Pre-processors
  3. Timers
  4. Samplers
  5. Post-processors
  6. Assertions
  7. Listeners
  8. How many threads should be allowed to run on a single machine at most?

It is dependent upon the hardware configuration of your system, which comprises, among other things, a CPU, a JVM, and allocated memory -Xmx. 

The number of processors or configuration items in your test plan, as well as whether you’re using GUI or non-GUI mode, all have an impact on the number of threads.

15. Which protocols does JMeter support?

JMeter supports many widely used protocols, including: 

  • Web: HTTP/HTTPs
  • Web Services: SOAP / XML-RPC
  • Database via JDBC drivers
  • Directory: LDAP
  • Messaging Oriented service via JMS
  • Service: POP3, IMAP, SMTP
  • FTP (File Transfer Protocol) Service

16. Is it feasible to capture actions on a mobile device using JMeter? In such a case, how would you approach it?

Yes, you can use JMeter to record queries sent to the server via your mobile application, either via HTTP or HTTPS. JMeter and Mobile need to be on the same network.

The configuration that is required is as follows:

  • Configure your proxy server in JMeter to execute on a designated port.
  • Use the same port number as the recorder when configuring the proxy in your phone’s WiFi settings.
  • Download and install the Root CA certificate on your mobile device.
  • Transmit server requests from your smartphone and watch as the controller of your choice gathers them.

17. Is it feasible for you to execute Selenium scripts with JMeter? In such a case, how would you approach it?

Yes, you can use JMeter to execute Selenium programs and see how well they work.

  • There are two approaches to this. One option is to write Selenium scripts using JUnit libraries and store them as Jars, which you can subsequently add to the JMeter directory. Next, import the Jar file and include the JUnit sampler in your test plan.
  • Alternatively, the Webdriver sampler plugin can be placed inside the JMeter ext folder. It’s time to restart JMeter. Write your Selenium code in the Webdriver sampler, then run it to see how it works.

18. How are cookies and sessions handled in JMeter?

Cookies and sessions in JMeter can be managed with configuration pieces like HTTP Cache Manager, which lets you add and remove user-defined cookies and clear cookies after each cycle. 

In load tests, the HTTP Cache Manager helps you limit the number of objects that can be cached and clean the cache after each iteration as needed. Both of these configuration parameters can be used to set up the HTTP sampler.

19. Create the code necessary to write JMeter variable data to a CSV file.

Use the following lines of code within a BeanShell postprocessor to write data to a CSV file. 

 dataString = vars.get(“DataToBeWritten”);

filePath = vars.get(“DataFilePath”);

 // you should pass true if you want to append the data to an existing file  

 // if you wish to overwrite, then do not pass the second argument 

 FileWriter fstream = new FileWriter(filePath, true);

 BufferedWriter out = new BufferedWriter(fstream);

 out.write(dataString);

 out.write(System.getProperty(“line.separator”));

 out.close();

 fstream.close();

The data is written to an already-existing file in the code above. The data in dataString is appended to the file, and the location of the current file is saved in filePath.

Conclusion

We hope this article on JMeter interview questions and answers has significantly increased your familiarity with JMeter-related subjects. With our JMeter training in Chennai, launch your software testing career.

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