Author Archives: Stanislav_Panteleev

🧠 First: What are GenericServlet and HttpServlet? Class Meaning GenericServlet An abstract class designed for any type of protocol (not just HTTP). HttpServlet A concrete class specifically for HTTP protocol (GET, POST, PUT, DELETE, etc.). Both help you avoid writing … Continue reading →

🧠 Full List of Important Servlet Listeners + Examples Listener Interface Purpose Example Event It Catches ServletContextListener App startup and shutdown Server starts your app, or app is undeployed HttpSessionListener Session creation and destruction User opens a session (new visit) … Continue reading →

🧠 Main Differences Between Filter and Listener Feature Filter Listener What it is Interceptor of requests and responses Event handler for lifecycle events When it runs Every time a matching request comes in When a specific event happens (like app … Continue reading →

🧠 What Are Servlet Wrapper Classes? Wrapper classes are special decorators that wrap around the original HttpServletRequest, HttpServletResponse, or ServletInputStream/ServletOutputStream. They allow you to: Intercept or modify behavior Read, change, or log request/response data Implement security, compression, caching, etc. In … Continue reading →

🧠 How to Get the Client’s IP Address in a Servlet ✅ The basic way: request.getRemoteAddr() returns the IP address of the client making the request. Example: If you’re testing locally ➔ might be 127.0.0.1. If a real client ➔ … Continue reading →

You can easily get server information from inside a servlet using the ServletContext and HttpServletRequest objects. Let’s go step-by-step: 🛠️ Ways to Get Server Info in a Servlet 1. Get Server Info using ServletContext ✅ serverInfo will return something like: … Continue reading →

🧠 If you want to get the real file system path (actual location) of a servlet or a resource on the server, you don’t get it directly from the servlet class itself. Instead, you use the ServletContext object, which represents … Continue reading →

🧠 First, can a servlet have a deadlock? Yes.Because servlets are multithreaded: One servlet instance is usually shared between many threads (one thread per request). If you mess with shared resources (like instance variables or external locks) incorrectly, you can … Continue reading →

Attributes are key-value pairs you can attach to an object like: ServletRequest HttpSession ServletContext They are used to share data between: Different parts of your servlet (methods, filters) Different servlets Requests across time (session)

Feature forward() (RequestDispatcher) sendRedirect() (HttpServletResponse) Who handles it Server Browser (client) How it works Server internally forwards the same request to another resource (another servlet, JSP, HTML, etc.) Server tells browser: “Hey, go make a new request to a different … Continue reading →