JUnit Interview Questions and Answers

Last updated on Mar 08, 2022
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JUnit Interview Questions

Junit is a unit testing framework and is an open source helping in test-driven development. It is used to write and run the Java programs’ test cases. Junit interview questions are one of the topics which take the students’ mind, and they search for the answers to it. There are several factors and the parameters increasing the use of JUnit framework. It also acts as a relationship-builder between development and testing process and is used for testing the application without any use of the server.


  • Increases stability and productivity of the program code
  • Reduces the debugging time
  • Decreases the chances of errors
  • Provides a text-based command line
  • Consists of Swing-based and AWT-based graphical testing for reporting the process

Most Frequently Asked JUnit Interview Questions

Here in this article, we will be listing frequently asked JUnit Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. What is JUnit?

Junit is an important unit Java testing framework and helps in the development of test-driven development. It is a significant part of the family known as xUnit, and hence it got its a name, Junit. Junit framework runs automatically improving the results and providing immediate feedback.

Q2. What is the use of JUnit?

Junit, an automation framework is used for UI testing and unit testing for the definition of the implementation of the code flown with different Annotations. It assists in writing the codes faster increasing the quality

Q3. What are the essential features of JUnit?
  • Flexibility- With the help of matches, Junit helps in the assertions of the multiple conditions such as any of(is(“Learn Junit)), constraintstring(“hello)));
  • Enhanced failure messages- In the previous version of JUnit, the coding of the failure message was- org.junit.ComparisonFailure:expected:<hello[] but was :<hello[world]> But in the new version of JUnit, the better is java.lang.AssertionError:Expected: is “hello” but: was &lquo;hello world”
  • Gives annotations for the identification of the test methods.
  • Junit offers test runners for the running tests and assertions for testing expected results.
  • It has simple and less complex taking less time in the operation of the testing process

Junit Interview Questions can be learned easily with us on this online learning platform.

Q4. How do you assert exceptions in JUnit?
Q5. What is the purpose of the @AfterClass annotation in JUnit?

In case of the allocation of the expensive external resources in a BeforeClass method, then there is the requirement of releasing them after the running of the tests completes. For this, the annotation of the @AfterClass method, a public static void method is required to be run after all the class’s tests have been run. It is because of the feature of the method such as it guarantees the test is running even in the situation of an exception thrown by BeforeClass. It is one of the methods to be declared in the superclass and run after the running process of the current class ends. Also, it is called once per test class.

Q6. What are JUnit annotations?

The special form of the syntactic meta-data that can be used for the improved code readability and structure in the source code. The examples of the entities that can be annotated are parameters, methods, variables, classes, and methods in the Java source code. JUnit annotations are Before, After, AfterClass, Ignore, BeforeClass, RunWith, and Test.

Q7. What is Junit testing?

Junit testing is a framework written in Java for providing a standard way of organizing, writing, and running the tests. An accurate logic of the test can be written following a simple rule. Here, Junit means unit testing which implies the meaning as of checking the individual parts of a software system without the implementation of the entire system from end to end.

Q8. Why do we use JUnit testing?
The multiple essential features of JUnit testing are the answer to the above question. Some of them are as follows-
  • Useful in providing the status of the result after testing, i.e., shows green on the smooth running of the test, whereas, red is the color in the otherwise case.
  • Test cases can be organized in the form of JUnit tests
  • Helps in the fast writing and execution of the codes
  • Junit testing helps in increasing the quality of the tests
Q9. How do I run a JUnit test from the command line?
Q10. Which is better JUnit or TestNG?
S.no TestNG Junit
1. Junit and NUnit inspires this testing framework Are a java library and an instance of xUnit architecture for Unit testing code chunks
2. Easier to use with the help of the new functionalities Some complexities are there
3. An XML file is required to run the suite test @Suite and @RunWith are required to run the suite test
4. Exception testing is available It is available here as well
5. New innovation feature is available in Group test No existence of any Group test here in JUnit
Development History

This open source framework was developed by Erich Gamma and Kent Beck. Look for the best Junit interview questions

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