Junit

Practice 15 Junit interview questions with detailed answers. Part of the Junit track on Java Interview Hub.

• What is JUnit, and why is it important for unit testing?
• Explain the difference between @Before and @BeforeClass. How are they used?
• How do you test expected exceptions in JUnit?
• What is the difference between assertEquals, assertTrue, and assertSame in JUnit?
• What are parameterized tests in JUnit, and how do they work?
• What is a test suite in JUnit, and how do you create it?
• How do you handle timeouts in JUnit?
• How do you structure a test case in JUnit?
• What is the purpose of the @Test annotation?
• How do you mock a static method in JUnit? Is it possible without external libraries?
• Can you explain how @RunWith and @Rule work in JUnit?
• How would you test private methods in JUnit? Should you test them directly?
• How do you write a test for a method with database calls in JUnit without hitting the actual database?
• How does JUnit handle concurrency when running multiple test methods in parallel?
• What are some best practices for writing unit tests using JUnit?