Regression testing is a crucial process in software development that involves retesting the modified parts of an application or system to ensure that the recent changes have not adversely affected the existing functionalities. The primary goal of regression testing is to identify any new defects or bugs that might have been introduced inadvertently during the latest code changes. Let's illustrate this with an example: Imagine you have developed an e-commerce website with a feature that allows users to search for products by various criteria. After a few weeks you decide to enhance the search functionality to include additional filters. Before deploying this new feature you would conduct regression testing to verify that the recent modifications have not caused issues with other parts of the website such as the checkout process or user accounts. By running regression tests developers can ensure that the software continues to perform as expected after each update preventing regression issues and maintaining the overall quality of the product. In practice regression testing can be automated using testing tools such as Selenium JUnit or TestNG which help save time and effort while ensuring thorough test coverage. Automation allows for quicker test execution making it easier to detect any regressions promptly and integrate testing seamlessly into the software development process. In summary regression testing is a valuable quality assurance technique that plays a vital role in maintaining the reliability and stability of software applications by verifying that new changes do not break existing features.