What is JUnit and how is it used for testing in Java?

JUnit is a popular Java testing framework that is used for automated unit testing. It allows developers to create test cases, test individual units or components of their Java code, and verify that the code behaves as expected.

Developers write test methods that define the expected behavior of code snippets and use assertions to validate that the code is working correctly. JUnit provides annotations such as @Test to mark test methods and @Before and @After to set up and tear down test fixtures.

By running JUnit tests, developers can quickly identify and fix bugs, ensure that new code changes do not break existing functionality, and improve the overall quality of their Java applications.

Overall, JUnit is an essential tool for Java developers to maintain code quality, increase productivity, and build reliable software applications.