Explain the concept of defect life cycle in software testing.

The defect life cycle in software testing refers to the various stages that a defect goes through from its identification to its resolution. It is a systematic process that helps in tracking and managing defects effectively. The defect life cycle typically consists of the following stages:

1. Defect Identification: This is the first stage where defects are identified either through manual testing or automated tools. Testers or developers may discover defects during various testing activities such as functional testing, integration testing, or system testing.

2. Defect Logging: Once a defect is identified, it needs to be logged into a defect tracking system or a bug tracking tool. The defect is assigned a unique identification number, and all relevant details such as the defect description, steps to reproduce, severity, priority, and the person responsible for fixing it are recorded.

3. Defect Triage: In this stage, the logged defects are reviewed and prioritized based on their severity and impact on the system. The defect triage team, which usually consists of project managers, testers, and developers, decides the priority of each defect and assigns it to the appropriate team member for further analysis and resolution.

4. Defect Analysis: Once a defect is assigned to a developer, they analyze the defect to understand its root cause and determine the necessary steps to fix it. They may need to reproduce the defect, debug the code, or perform additional testing to identify the underlying issue.

5. Defect Fixing: After analyzing the defect, the developer fixes the code to resolve the defect. They make the necessary changes to the software application and ensure that the defect is eliminated.

6. Defect Verification: Once the defect is fixed, it undergoes verification to ensure that the fix is successful and the defect no longer exists. Testers retest the software to validate that the defect has been resolved and does not reoccur.

7. Defect Closure: If the defect is verified successfully, it is marked as closed in the defect tracking system. The defect is considered resolved, and no further action is required. However, if the defect is not fixed or reoccurs, it is reopened and goes through the defect life cycle again.

The defect life cycle provides a structured approach to managing defects, ensuring that they are properly tracked, analyzed, and resolved. It helps in maintaining the quality of the software application by minimizing the number of defects and improving the overall reliability and performance of the system.