Describe the life cycle of a Java Servlet with a suitable diagram and explain the purpose of its major methods.

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## Life Cycle of a Java Servlet

A **Servlet** is a Java server-side component that handles requests and generates responses, commonly in a web container such as Apache Tomcat.

```mermaid
flowchart TD
  A[Container loads servlet class] --> B[Create servlet instance]
  B --> C[init called once]
  C --> D[service handles each request]
  D --> E[doGet / doPost / other handler]
  E --> F[Send response]
  F --> D
  D --> G[Servlet removed or application stopped]
  G --> H[destroy called]
```

**Life-cycle methods**
1. **Loading and instantiation:** the container loads the servlet class and creates an instance.
2. **init():** called once after instantiation to initialize resources such as configuration or connections.
3. **service():** invoked for requests; in HttpServlet, it dispatches requests to methods such as doGet() and doPost().
4. **doGet():** commonly handles retrieval/read requests.
5. **doPost():** commonly handles submitted data or operations that change server state.
6. **destroy():** called before the servlet is taken out of service so it can release resources.

**Request processing:** the container maps a URL to the servlet, creates request and response objects, invokes the appropriate handler, and sends the generated response to the client.

**Threading note:** containers may process concurrent requests using multiple threads, so shared mutable fields must be handled carefully. Request-specific data should generally remain local to a request.

**Conclusion:** The servlet container manages the lifecycle, while the servlet's methods initialize resources, process requests and clean up resources.

Life Cycle of a Java Servlet

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