Understanding Servlet Lifecycle Methods Explained with Examples

Are you curious about the inner workings of Servlets and how they handle client requests? Let’s delve into the fascinating life cycle of a Servlet, dissecting the init(), service(), and destroy() methods, with detailed explanations and code examples.

1. Initialization (init()): The init() method serves as the Servlet’s initialization phase. When the server first loads the Servlet into memory or upon receiving the first client request, the init() method is invoked. This method is where you perform any necessary setup tasks, such as initializing resources, configuring parameters, or establishing database connections.

public class MyServlet extends HttpServlet {
    
    public void init() throws ServletException {
        // Initialization code here
        System.out.println("Servlet Initialized");
    }
}

2. Request Processing (service()): The service() method is the heart of the Servlet, responsible for handling client requests. Whenever a client sends a request to the server that maps to the Servlet, the service() method is called. Inside this method, you process the client’s request, generate the appropriate response, and send it back to the client.

public class MyServlet extends HttpServlet {
    
    protected void service(HttpServletRequest request, HttpServletResponse response) 
            throws ServletException, IOException {
        // Request processing code here
        System.out.println("Request Received");
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<h1>Hello World!</h1>");
    }
}

3. Destruction (destroy()): Just like every story has an ending, every Servlet has a conclusion. The destroy() method marks the end of the Servlet’s life cycle. When the server shuts down or decides to unload the Servlet to reclaim memory resources, the destroy() method is called. This is where you perform any cleanup tasks, release resources, or gracefully shut down connections.

public class MyServlet extends HttpServlet {
    
    public void destroy() {
        // Cleanup code here
        System.out.println("Servlet Destroyed");
    }
}

Ready to dive deeper into Servlet development? Stay tuned for more insightful guides and tutorials on mastering Servlets and Java-based web technologies!