Java Programming Basics with Examples

What is a Servlet? A Servlet is a server-side Java program that runs inside a web server and is used to handle client requests and generate responses. Servlets can perform different types of logic, such as: Presentation Logic – Generating output (HTML, JSON, etc.) Business Logic – Processing application rules and conditions Persistence Logic – Interacting with databases Response Handling – Sending the response back to the client Servlets act as a bridge between the client (browser) and the server-side application logic. 🔹 Secure Web Application Development Using Servlets To develop a secure Java web application, a programmer must use the Servlet API. 🔸 servlet-api.jar servlet-api.jar is a library that provides all Servlet and HTTP-related classes and interfaces. This JAR file is present inside the Apache Tomcat server. 📂 Location in Tomcat Apache Tomcat → lib → servlet-api.jar 🔹 Role of servlet-api.jar       Acts as a runtime environment for servlet applications. ...

What are Servlets? Servlets are Java programs that run on a server and handle client requests, usually coming from a web browser. They are mainly used to build dynamic web applications. Servlets run inside a server environment, which can be classified into: Web Server Application Server 🔹 Web Server A Web Server is a server that contains: Web Server Engine Web Container 🔸 How a Web Server Works A client (browser) sends a request. The web server receives the request. The request is forwarded to the web container. The web container processes the request. A response is generated and sent back to the browser. 🔸 Role of Web Container       Provides a runtime environment for web applications.      Can run only web applications, such as: Servlet applications Spring applications Struts applications 🔸 Web Server Limitations Cannot run enterprise applications (EJB, distributed systems). 🔸 Examples of Web Servers Apache Tomcat GlassFish 🔹 Application Server An ...