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In modern microservice architectures, Redis is widely used for caching, distributed locking, session storage, and rate limiting. However, the way you interact with Redis differs significantly between a traditional Servlet‑based service (blocking) and a WebFlux‑based gateway (non‑blocking). This guide explains both approaches and provides ready‑ ...

Java Enterprise Context The Java Enterprise Edition (JavaEE) specification, former known as J2EE, defines standards for enterprise application development. Managed by the Java Community Process (JCP), it includes technologies like Servlets, JSP, JDBC, and JPA. The current version is JavaEE 8. Web Fundamentals The World Wide Web (WWW) provides a ...

Database Implementation Components Entity Class public class Person { private String fullName; private String years; private String gender; public Person(String fullName, String years, String gender) { this.fullName = fullName; this.years = years; this.gender = gender; } // Getters and setters ...

Exact Path Mapping An exact match occurs only when the request URL is identical to the string defined in the <url-pattern> tag. This is the most specific form of routing. <servlet-mapping> <servlet-name>resourceHandler</servlet-name> <url-pattern>/secure/login</url-pattern> </servlet-mapping> h ...

1 Session Management Fundamentals 1.1 Session Management Overview 1.1.1 Defining a Session In web development, a session represents a complete communication cycle between the client and server. The session begins when a user opens a browser and navigates to a website, and terminates when the browser closes or the session expires. Consider this ...

The HttpSession interface in Java Servlets enables servers to maintain user-specific state across multiple HTTP requests. When a client makes its first request, the server creates a session and assigns it a unique identifier (JSESSIONID). This ID is sent to the client as a cookie. Subsequent requests from the client include this cookie, allowin ...

Creating a Basic Servlet To begin learning Servlet development, we start with a simple Hello World example. Create a dynamic web project in you're IDE, then define a new Servlet class. package com.example.demo; import java.io.*; import javax.servlet.*; import javax.servlet.annotation.WebServlet; import javax.servlet.http.*; @WebServlet(" ...

Servlet Filters Filters are a core component of the Java Servlet specification, operating within the servlet container to pre-process requests and post-process responses. They execute before a request reaches a servlet and after the servlet generates a response, enabling tasks like logging, authentication, and data transformation. Core Conecpts ...

The lifecycle of a Servlet is managed by the container and consists of four distinct phases: Creation: Occurs once, during the first request. Initialization: Happens once, immediately after instantiation. Service Execution: Invoked multiple times, once per request. Destruction: Executed once, when the container shuts down. When a client makes ...

Maven coordinates <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelV ...