What is the life cycle of a servlet?

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Each Servlet has the same life cycle: a) A server loads and initializes the servlet by init () method. b) The servlet handles zero or more client’s requests through service() method. c) The server removes the servlet through destroy() method.

The life cycle of a servlet in Java is defined by the Servlet interface. The key methods that define the servlet life cycle are:

  1. Initialization (init): This method is called by the servlet container when the servlet is first loaded. It is used to perform any one-time initialization tasks, such as loading configuration parameters or establishing database connections. The init method is called only once during the servlet’s life cycle.
    java
    public void init(ServletConfig config) throws ServletException {
    // Initialization code goes here
    }
  2. Request Handling (service): The service method is called by the servlet container for each request. It is responsible for processing the client’s request and generating the appropriate response. The service method is called multiple times during the servlet’s life cycle, once for each request.
    java
    public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
    // Request handling code goes here
    }

    Note: While the service method is the primary method for handling requests, it is often overridden indirectly by implementing the doGet, doPost, doPut, etc., methods for handling specific HTTP methods.

  3. Destruction (destroy): The destroy method is called by the servlet container when it decides to unload the servlet. This might happen when the web application is being shut down or when the servlet container decides to reclaim resources. The destroy method allows the servlet to perform cleanup tasks, such as closing database connections or releasing other resources.
    java
    public void destroy() {
    // Cleanup code goes here
    }

During the life cycle of a servlet, the init method is called once, the service method is called for each request, and the destroy method is called when the servlet is being unloaded. These methods together define the life cycle of a servlet in Java.