The server has multiple threads that are available to handle requests. When a request comes in, it is assigned to a thread, which calls a service method (for example: doGet(), doPost() and service()) of the servlet. For this reason, a single servlet object can have its service methods called by many threads at once.

Servlets in Java handle multiple simultaneous requests through multithreading. When a servlet is deployed, the servlet container (like Apache Tomcat) creates a single instance of the servlet class. However, multiple threads are used to handle different requests concurrently.

Here’s how the process generally works:

Servlet Instance: The servlet container creates an instance of the servlet when the first request for that servlet is received.
Multithreading: Each incoming request is handled by a separate thread. The servlet container can have a pool of threads that it uses to process requests. When a new request comes in, a free thread from the pool is assigned to handle that request.
Thread Safety: Servlet developers need to ensure that their servlet classes are thread-safe. This means that the servlet can be safely accessed and modified by multiple threads at the same time without causing unexpected behavior. Developers often use synchronization mechanisms to achieve thread safety.
Request and Response Objects: Each thread is given its own HttpServletRequest and HttpServletResponse objects, so different requests do not interfere with each other.
Life Cycle Methods: The init(), service(), and destroy() methods of the servlet are called by the container during various stages of the servlet’s life cycle. The service() method is particularly important for handling requests. It is called by the container for each request, and it, in turn, calls the appropriate method (e.g., doGet() or doPost()).

By handling requests in separate threads, servlets can efficiently manage multiple simultaneous requests, providing a scalable and responsive solution for web applications.