# StacKnowledge

> Stack of Knowledge and Experience


## Posts

- [File Systems vs. Distributed Storage: Architecture, Scaling, and Real-World Trade-Offs](https://stacknowledge.in/blogs/file-system-vs-distributed-storage/): Every application relies on storage, yet the way systems store and retrieve data has shifted dramatically over the past two decades. Modern data-intensive applications—ranging from streaming platforms to machine learning pipelines—process petabytes of incoming records every day. A single hard drive or traditional server simply cannot handle this volume. To overcome these constraints, engineers transitioned from isolated local storage to distributed file systems (DFS). This article explores how storage architecture evolved, examines the mechanics of distributed replication, compares popular enterprise storage solutions, and highlights essential design trade-offs. What Is a Traditional File System? At its core, a storage drive is merely a […]
- [Object Storage in Modern Systems: Architecture, Use Cases, and Design Patterns](https://stacknowledge.in/blogs/object-storage/): Modern cloud platforms demand storage solutions that can scale seamlessly to petabytes and exabytes. Traditional file systems and disk-attached block storage often crumble under the weight of billions of unstructured files. Consequently, object storage has become the undisputed backbone of modern cloud-native architectures. Whether you stream videos on YouTube, run machine learning training pipelines, or archive petabytes of compliance logs, object storage provides the durability, scalability, and cost efficiency that distributed applications require. What Is Object Storage? Unlike traditional systems that organize data into nested directories or raw disk sectors, object storage stores data as discrete, self-contained units called objects. Every object packages three […]
- [Advanced Database Architecture: Scaling Strategies, Replication, Sharding, and Polyglot Persistence](https://stacknowledge.in/blogs/database-scaling-replication-sharding-polygot-persistence/): Modern web applications serve millions of concurrent users, process petabytes of information, and demand round-the-clock availability. When an application outgrows its initial prototype, the database almost always becomes the primary bottleneck. To overcome these performance walls, system architects rely on four foundational pillars: This guide breaks down each strategy in clear, plain language, examines their real-world trade-offs, walks through production case studies from Netflix and Uber, and provides an end-to-end architectural blueprint. Scaling Strategies: SQL (Vertical) vs. NoSQL (Horizontal) When traffic surges, databases slow down. Software teams generally take one of two paths to address this bottleneck: scale up (vertical scaling) […]
- [SQL vs. NoSQL: Guide to Choosing the Right Database Model](https://stacknowledge.in/blogs/sql-vs-nosql-database-models-polygot/): Introduction: Why Database Selection Dictates System Success Every meaningful software application requires data to survive beyond a single server restart or HTTP request. A database serves as the foundation of your system, providing persistent storage while allowing applications to query, filter, update, and manage state efficiently. Modern systems treat the database as their ultimate source of truth. However, scaling an application from a simple prototype to an enterprise platform serving millions of concurrent users introduces complex trade-offs. Engineers face a fundamental architectural choice: SQL (Relational) or NoSQL (Non-Relational). Rather than asking which database is universally superior, architects evaluate how well a database model aligns […]
- [Storage Fundamentals and the CAP Theorem in Modern System Design](https://stacknowledge.in/blogs/storage-fundamentals-cap-theorem/): Introduction: Why Storage Dictates System Scalability Every scalable digital product revolves around one critical asset: data. Users generate information, microservices process it, and businesses depend on retaining it accurately over time. Whenever data must survive beyond a single HTTP request or an abrupt server reboot, storage stops being an afterthought and becomes the core pillar of your system architecture. Storage choices determine your application’s response latency, operational overhead, fault tolerance, and cost efficiency. For example, pairing a blazing-fast application server with an unoptimized disk subsystem creates severe bottlenecks. Similarly, utilizing an unreliable storage tier can turn a minor network hiccup into catastrophic […]
- [Cloud Auto-Scaling: Architecture, Strategies and Best Practices](https://stacknowledge.in/blogs/cloud-auto-scaling-architecture-strategies/): Introduction: What Is Auto-Scaling and Why Does It Matter? Modern applications rarely face constant, predictable traffic. An e-commerce platform might experience a sudden influx of shoppers during a flash sale, whereas an enterprise accounting tool might see virtually zero traffic at midnight. When systems encounter unpredictable demand spikes, systems engineers cannot manually add or remove servers quickly enough to keep services running smoothly. Auto-scaling solves this fundamental operational challenge. It automatically provisions or deprovisions computing resources in real time to match incoming application workload. Traffic Surges ───► Auto-Scaling Adds Compute ───► Zero Downtime & Fast ResponseTraffic Drops ───► Auto-Scaling Cuts Capacity ───► […]
- [Understanding Load Balancers: Strategies, and Architecture](https://stacknowledge.in/blogs/load-balancers-scalability-routing-availability/): What Is a Load Balancer and Why Do You Need One? When an application starts with a single server, everything feels simple. The server receives requests, processes database queries, and returns responses. However, as traffic surges, this single machine quickly hits physical limits in CPU, memory, and network throughput. Consequently, that machine becomes both a severe performance bottleneck and a dangerous Single Point of Failure (SPOF). If that single server crashes, your entire business goes offline. A load balancer resolves this vulnerability by acting as an intelligent reverse proxy and traffic cop situated between your users and your fleet of backend servers. Instead of […]
- [System Scalability 101: Guide to Scaling Strategies, Trade-Offs, and Architecture](https://stacknowledge.in/blogs/system-scalability-strategies-trade-offs-architecture/): What Is Scalability? Every growing business faces a critical milestone: user traffic increases, transactions surge, and existing servers begin to strain under the pressure. A system that seamlessly serves 1,000 users can suddenly buckle when 100,000 or 1,000,000 users arrive at the same time. At its core, scalability measures a system’s ability to handle growing workloads gracefully without sacrificing performance, reliability, or user experience. Scalability Test Normal Load (1K Users) Peak Load (1M Users) ┌─────────────────────────────┐ ┌─────────────────────────────┐ │ Response Time: < 100 ms │ │ Response Time: < 120 ms │ │ Availability: 99.99% │ ──> │ Availability: 99.99% │ │ Architecture: Stable […]
- [Understanding CORS and Same-Origin Policy: Guide to Secure Web Communication](https://stacknowledge.in/blogs/cross-origin-resource-sharing-and-same-origin-policy/): Modern web architectures often distribute services across multiple servers, domains, and cloud environments. For instance, a single-page application might run on https://app.com, while its backend data resides on https://api.com. Consequently, browsers must constantly balance the need for system connectivity with the imperative of user security. In this article, we will examine how web browsers enforce security boundaries using the Same-Origin Policy (SOP) and Cross-Origin Resource Sharing (CORS), examine real-world use cases, and explore architectural alternatives like reverse proxies and API gateways. Why Web Security Needs the Same-Origin Policy (SOP) Web security relies heavily on the Same-Origin Policy (SOP). Introduced by Netscape in 1995, this […]
- [Serialization: The Backbone of Modern Data Exchange and Storage](https://stacknowledge.in/blogs/serialization/): In modern distributed systems, data constantly moves across networks, databases, caches, and microservices. However, a fundamental challenge exists: computer applications manage data using in-memory objects, whereas network sockets and storage systems only understand sequential streams of bytes. To bridge this gap, developers rely on serialization. This article explains what serialization is, compares the most popular data exchange formats, and helps you choose the right format for your system architecture. What is Serialization? At its core, serialization is the process of converting an in-memory application object or data structure into a standardized, portable format. This format can be transmitted over a network or saved to […]
- [Web Sessions: A Complete Guide to State Management in Web Applications](https://stacknowledge.in/blogs/web-sessions-stateless-stateful/): Have you ever wondered how a website remembers you are logged in, keeps items in your shopping cart, or saves your preferences as you navigate from page to page? The magic behind this seamless experience is session management. In this guide, we will break down how web sessions work, explore the techniques developers use to manage state, and compare the two dominant approaches: Session-Based and Token-Based authentication. The Core Challenge: HTTP is Stateless To understand sessions, we must first understand the underlying protocol of the web: HTTP (Hypertext Transfer Protocol). HTTP is fundamentally stateless. This means each request sent from your browser to a server is a completely […]
- [Event-Driven Architecture: Building Scalable, Responsive Systems](https://stacknowledge.in/blogs/event-driven-architecture/): Modern distributed applications demand speed, scalability, and resilience. However, traditional systems often struggle to meet these requirements because they rely on tight coupling and direct service-to-service communication. As systems grow, this synchronous request-response web creates latency bottlenecks and single points of failure. To solve these challenges, software architects turn to Event-Driven Architecture (EDA). By communicating through events rather than direct calls, EDA decouples services and enables them to run independently. Consequently, systems become more responsive, flexible, and adaptable to change. In this guide, we will explore the core concepts of EDA, compare communication styles, analyze key patterns, and detail the best practices […]
- [Microservices Architecture: A Complete Guide to Modern Scalability](https://stacknowledge.in/blogs/microservices-architecture/): In today’s fast-paced digital world, applications must grow and adapt quickly. When systems expand, traditional monolithic architectures often slow down development, deployment, and scaling. To solve this problem, software architects use microservices architecture—a modern approach that breaks large systems into small, independent, and resilient services. In this guide, you will learn what microservices are, how they communicate, how to scale them, and how they solve real-world challenges. What is Microservices Architecture? A microservices architecture is a software design pattern that builds an application as a collection of small, loosely coupled services. Each service is responsible for a single business capability (like payments or user […]
- [Understanding Multi-Tier Architecture: From 2-Tier Simplicity to Modern N-Tier Scale](https://stacknowledge.in/blogs/multi-tier-architecture-from-2-tier-to-modern-n-tier/): Separation of concerns is the foundational rule of software design. As applications expand, bundling the user interface, business rules, and database access into a single monolith creates a system that is difficult to scale, test, and secure. A single code update can trigger unexpected side effects across the entire application. Multi-tier architecture solves this issue by dividing applications into distinct physical and logical layers. Each tier handles a specific concern—typically separating user interaction, business processing, and data storage. What Is Multi-Tier Architecture? Multi-tier architecture separates an application’s functions into independent layers. This separation establishes clear operational boundaries and grants teams the […]
- [Software Architecture: Patterns, Trade-Offs, and Real-World Choices](https://stacknowledge.in/blogs/software-architecture-patterns-monolithic-layered-microservices-event-driven/): Choosing the right software architecture is one of the most critical decisions an engineering team makes. While code implementation details change daily, architectural choices define how a system scales, performs, and evolves over years. Understanding software architecture patterns enables you to select the right blueprint for your system based on business requirements, team size, and technical complexity. What is Software Architecture? Software architecture represents the high-level structure of a system. It defines the primary components, their distinct responsibilities, and the mechanisms by which they communicate. Unlike code-level design patterns (like Strategy or Factory patterns), system architecture focuses on operational characteristics: Core […]
- [Real-Time Communication Protocols: WebSockets vs. Long Polling](https://stacknowledge.in/blogs/real-time-communication-protocols-long-polling-websockets/): In modern software development, users expect systems to react instantly. Whether you are checking stock prices, chatting with colleagues, or playing a multiplayer game, waiting for a manual page refresh feels slow and outdated. Traditional HTTP relies on a simple request-response model that works well for loading static content. However, it struggles when information changes continuously. To deliver immediate updates, low-latency experiences, and live interactions, developers rely on real-time communication protocols. Choosing the right protocol requires understanding the trade-offs between latency, system scalability, and operational complexity. The Genesis: From Short Polling to Long Polling Before persistent connections became widely supported, applications […]
- [Modern API Protocols: Beyond REST to gRPC and GraphQL](https://stacknowledge.in/blogs/beyond-rest-grpc-graphql/): For years, REST (Representational State Transfer) has served as the backbone of web APIs. However, as software systems evolve into complex microservices and high-performance frontend applications, traditional RESTful patterns present significant bottlenecks. Issues like data overfetching, underfetching, high latency, and lack of native bidirectional streaming have pushed software architects to adopt alternative API paradigms. Two technologies leading this shift are gRPC and GraphQL. While both address the limits of REST, they optimize for entirely different layers of the software architecture: +-------------------------+ | Clients (Web / Mobile) | +------------+------------+ | | GraphQL (HTTP/JSON - Flexible Queries) v +-------------------------+ | GraphQL Gateway / […]
- [REST & RESTful API Design: The Complete Architecture Guide](https://stacknowledge.in/blogs/rest-representational-state-transfer/): Building scalable web applications requires a predictable, clean way for clients and servers to exchange data. REST (Representational State Transfer) has emerged as the standard architectural style for building modern web applications, providing a reliable foundation for distributed systems. What is REST? REST is an architectural style that leverages existing web standards, primarily HTTP. Instead of creating complex custom communication protocols, REST treats every system entity as a resource. Clients access, create, update, or delete these resources using standard HTTP verbs. +-------------------------------------------------------------------+| CLIENT - SERVER || || +------------------+ +--------------------+ || | | --- HTTP GET ---> | | || | Client […]
- [Understanding HTTP: The Architectural Foundation of the Web](https://stacknowledge.in/blogs/http-hyper-text-transfer-protocol/): HyperText Transfer Protocol (HTTP) serves as the primary protocol enabling browsers, mobile applications, and backend microservices to exchange data reliably. Whether loading a webpage, invoking a RESTful API endpoint, or fetching media assets, HTTP manages the communication between clients and servers. The HTTP Request-Response Cycle HTTP relies on a synchronous request-response model. A client (such as a browser or API consumer) opens a TCP connection and sends a structured request. The target server processes the payload, executes necessary business logic, and returns a response. +----------------+ +----------------+| | --- 1. HTTP Request ---> | || Client App | | Web Server || […]
- [Blue-Green Deployments: A Modern Guide to Zero-Downtime Releases](https://stacknowledge.in/blogs/blue-green-deployment/): Modern software engineering demands continuous delivery without sacrificing platform availability. Consequently, engineering teams can no longer afford maintenance windows that interrupt the user experience. Blue-green deployment solves this exact challenge by enabling seamless, zero-downtime application updates. Historically, software updates required developers to stop application servers, apply changes, and restart services during off-peak hours. However, as global digital platforms grew, downtime became unacceptable. Pioneered by software experts Jez Humble and Martin Fowler in the late 2000s, the blue-green deployment strategy emerged as a foundational pattern for continuous delivery. By maintaining two identical production environments, engineering teams eliminated scheduled downtime and simplified rollback […]
- [TCP vs UDP: Choosing the Right Transport Protocol for Your Architecture](https://stacknowledge.in/blogs/tcp-vs-udp-transport-protocol-for-your-architecture/): Modern web applications depend heavily on transport layer protocols to move data across unpredictable networks. Network traffic faces delays, packet loss, and out-of-order delivery. Therefore, software architects must choose between Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) based on trade-offs between absolute reliability and low latency. This guide explores how TCP and UDP operate, their key differences, real-world use cases, and how to select the right protocol for your system design. Transmission Control Protocol (TCP) TCP prioritizes correctness and data integrity over raw speed. It creates a reliable communication channel over unstable networks by adding tracking, acknowledgments, and ordering […]
- [Securing Modern Web Apps: Integrating SRI & CSP with Nonces and Hashes](https://stacknowledge.in/blogs/securing-modern-web-apps-integrating-sri-csp-with-nonces-and-hashes/): Modern web developers rely heavily on external Content Delivery Networks (CDNs) to load essential JavaScript libraries and CSS stylesheets. While this approach improves performance and reduces server load, it introduces serious security risks. If a malicious attacker compromises a third-party CDN, they can inject malicious code directly into your users’ browsers. Fortunately, combining Subresource Integrity (SRI) and a robust Content Security Policy (CSP) creates a multi-layered defense mechanism that guarantees file integrity and prevents unauthorized code execution. What is Subresource Integrity (SRI)? Subresource Integrity is a powerful browser security feature that validates external assets before executing them. Specifically, developers generate a […]
- [Modern Systems Design: Mastering Content Delivery Networks (CDNs)](https://stacknowledge.in/blogs/content-delivery-networks-cdns/): In today’s hyper-connected world, milliseconds directly impact user retention and revenue. When your application grows globally, routing every single user request back to a single central data center quickly creates massive performance bottlenecks. A Content Delivery Network (CDN) solves this fundamental challenge. It acts as an intelligent, distributed execution and caching layer that sits between your users and your origin infrastructure. In this article, we will break down how modern CDNs work, explore their internal architecture, evaluate key routing strategies, and analyze real-world use cases. Why Modern Systems Need a CDN When every request must travel across continents to hit an […]
- [Understanding the API Gateway: The Front Door of Modern Architecture](https://stacknowledge.in/blogs/api-gateway/): As software systems grow in complexity, managing API traffic, security, and service interactions becomes increasingly challenging. When a system evolves from a monolithic setup into a distributed microservices environment, connecting every client directly to every backend service creates tight coupling. It pushes overwhelming complexity to the edge of your system. Fortunately, an API Gateway solves this exact problem by acting as a single, centralized entry point between consumers and your backend ecosystem. What is an API Gateway? An API gateway is an architectural pattern implemented as a server that intercepts all incoming client requests, processes them, and routes them to the […]
- [Scaling Beyond One Server: An Introduction to Load Balancing](https://stacknowledge.in/blogs/introduction-load-balancing/): Imagine launching a new web application. In the beginning, everything runs perfectly. Your app lives on a single server, and it handles early users with ease. But what happens when success arrives? As your user base grows, thousands of concurrent requests flood your system. Suddenly, that reliable single server slows to a crawl or crashes entirely. This scenario is a rite of passage for growing digital platforms. To survive this stage, you must transition from a single-machine setup to a distributed architecture. At the heart of this transformation lies one critical component: the load balancer. The Danger of the Single-Server Bottleneck […]
- [Network Proxies: Forward Proxy vs. Reverse Proxy](https://stacknowledge.in/blogs/forward-reverse-proxy/): When you navigate the web, your data doesn’t always travel in a direct line from your computer to the target website. Instead, it frequently passes through a layer of abstraction known as a proxy server. A proxy server acts as an intermediary system sitting right between a client (like your browser) and a destination server. When you make a request, the proxy intercepts it, sends it along to the final server, receives the response, and relays it back to you. While that sounds simple, proxies operate in two distinct directions: Forward Proxies and Reverse Proxies. Understanding how they differ is crucial […]
- [Understanding the Client-Server Model: The Backbone of Modern System Design](https://stacknowledge.in/blogs/client-server-model/): Every time you search for a topic online, check your social media feed, or stream a video, you rely on a fundamental architectural pattern: the client-server model. This core concept powers everything from simple websites and mobile applications to massive distributed systems and cloud APIs. If you want to build scalable, reliable software, you must understand how clients and servers interact. This article breaks down the client-server model in simple terms, covering its core components, communication styles, real-world use cases, and key interview questions. What is the Client-Server Model? The client-server model is a distributed computing structure that divides tasks or […]
- [Domain Name System (DNS): How the Internet's Directory Scale Globally](https://stacknowledge.in/blogs/domain-name-system-dns-how-the-internets-directory-scale-globally/): Every time you enter a domain name into your browser, a fascinating sequence of distributed system interactions happens behind the scenes. While users see a website load instantly, engineers know that a highly orchestrated workflow just took place. DNS acts as the internet’s directory service. It translates human-friendly names like google.com into the machine-readable IP addresses (192.0.2.1 or 2001:db8::1) that computers actually use to communicate. Beyond improving usability, DNS enables the modern internet to scale. Because cloud infrastructure runs across multiple shifting servers, data centers, and regions, IP addresses change constantly. DNS provides a stable layer of abstraction. It allows users […]
- [IP Addresses in System Design](https://stacknowledge.in/blogs/ip-addresses-in-system-design/): When you design distributed systems, IP addresses stop being a low-level networking detail and become a foundational building block. Before we can analyze how modern applications communicate, scale, and route traffic across the globe, we must understand the fundamental identity of every device on a network: the IP address. Every request, service call, and database connection ultimately depends on systems being able to locate each other reliably. This article explores the architectural role of IP addresses, their various types, and how they impact scalable system design. The Role of IP Addresses in System Design Think about what happens when a request […]
- [System Design: Building Scalable Software Architecture](https://stacknowledge.in/blogs/system-design-building-scalable-software-architecture/): When you hear the term System Design, you might immediately picture complex architectural diagrams, massive databases, and clusters of servers. While these components are vital parts of the equation, system design truly focuses on solving real-world business problems through smart technology choices. Think of system design as creating a comprehensive blueprint for a software system before construction begins. Just as an architect drafts structural plans before workers pour concrete, software engineers must design how components interact before writing lines of code. What is System Design? At its core, system design is a decision-making framework. It forces engineers to answer critical architectural […]
- [AEM MSM: How to Manage Live Copy Relationships](https://stacknowledge.in/blogs/aem-msm-live-copy-relationship-delete-issue/): In a previous discussion on AEM MSM: Multilingual & Multichannel with Custom Rollout, the foundation for creating tailored rollout actions was established. However, when large, multi-channel websites are managed, deep repository complexities are often encountered. Specifically, the way rollout configurations are inherited, linked, broken, or permanently blocked by page deletions must be fully understood. In this continuation, the hidden Java Content Repository (JCR) structures are broken down in simple terms, and a clear, programmatic solution is provided for a notorious built-in limitation: the cq:excludedPaths trap. How Rollout Configurations Are Stored in a Live Copy Node When a Live Copy page is […]
- [Architectural Orchestration: Overcoming Microservice Scaling Challenges via Kubernetes](https://stacknowledge.in/blogs/architectural-orchestration-overcoming-microservice-scaling-challenges-via-kubernetes/): The Inherent Difficulties of Scaling Microservices The architecture of distributed applications presents severe operational friction when scaling is attempted. In a monolithic application, scaling simply involves duplicating the entire application stack across larger servers. However, splitting an application into independent microservices introduces a complex web of distributed computing challenges where every operational dimension becomes harder to manage manually: Scheduling Workload placement is rendered exceptionally difficult because manual intervention cannot keep pace with rapidly shifting system demands. When a new service instance needs to be deployed, a node must be selected based on dozens of real-time variables, such as current CPU utilization, […]
- [OSGi Service References: Managing Multiple Implementations in AEM](https://stacknowledge.in/blogs/osgi-service-references-multiple-implementation/): In enterprise Adobe Experience Manager (AEM) development, modular architectures are heavily reliant on the OSGi framework. When building highly scalable applications, multiple implementations of a single interface are frequently deployed. To manage these scenarios efficiently, the OSGi declarative services specification provides robust mechanisms. Specifically, the @Reference annotation is utilized, where cardinality and policy options must be precisely configured to handle multiple service providers. Understanding Cardinality and Policy in OSGi When a component requires access to OSGi services, the relationship is defined by cardinality. Cardinality dictates whether the reference is mandatory or optional, and whether it accepts a single instance or multiple […]
- [Thread.sleep() vs ScheduledExecutorService: Java Concurrency and Scheduling Guide](https://stacknowledge.in/blogs/thread-sleep-vs-scheduledexecutorservice-java-concurrency/): In modern Java application development, asynchronous task execution and timing control are frequently required. For a long time, pausing thread execution was managed via Thread.sleep(). However, as enterprise systems evolved, the Java Concurrency Utilities introduced the ScheduledExecutorService. Selecting the correct approach is critical for application performance and resource management. This article provides a comprehensive comparison between these two paradigms, exploring their architectural differences, specific use cases, and concrete code implementations. Architectural Conceptualization The primary differentiator between these two methods lies in how threads are utilized and managed within the Java Virtual Machine (JVM). +-----------------------------------------------------------------------------------------------------+| JVM Memory Space |+-----------------------------------------------------------------------------------------------------+ | | v […]
- [Extending AI Capabilities: Building and Connecting a Custom MCP Server](https://stacknowledge.in/blogs/custom-mcp-server-build-connect-ai-agent/): In the previous article, we explored the fundamentals of the Model Context Protocol (MCP) and how it enables AI clients (like GitHub Copilot or custom agents) to interact with external systems in a structured, tool-driven way. Now, let’s take the next step — building a real MCP server using Node.js and connecting it to an MCP client to unlock powerful capabilities such as: What We’re Building We will build an MCP server that: Project Setup package.json Project needs just three key dependencies: Why these dependencies? MCP Server Implementation Step 1: Initialize MCP Server Step 2: Configure AEM Connection This allows secure […]
- [Model Context Protocol (MCP): A Complete Guide](https://stacknowledge.in/blogs/model-context-protocol/): The Model Context Protocol (MCP) is emerging as a foundational standard in modern AI systems, especially in the era of agentic AI—where AI systems don’t just respond, but actively reason, plan, and act. At its core, MCP solves a critical limitation of traditional AI models: They are powerful—but isolated from real-world data, tools, and actions. MCP bridges this gap by enabling AI models to connect with external systems in a standardized way, making them far more dynamic, useful, and autonomous. What is MCP? The Model Context Protocol (MCP) is an open standard that allows AI applications and large language models (LLMs) […]
- [Apache Maven: POM & BOM](https://stacknowledge.in/blogs/apache-maven-bom-pom/): Modern software projects often consist of dozens (or hundreds) of dependencies. Managing versions, transitive dependencies, consistency, and build logic manually quickly becomes chaotic. Apache Maven addresses this complexity using two foundational concepts: Though related, they serve distinct purposes in dependency and build management. What is POM (Project Object Model)? A POM is the core configuration file of a Maven project. It defines: Every Maven project must have one POM file, named: pom.xml ┌──────────────────────────┐│ pom.xml ││ (Project Object Model) │└──────────┬───────────────┘ │ │ Defines ▼┌──────────────────────────┐│ Dependencies ││ Plugins ││ Build Lifecycle ││ Packaging (jar/war) ││ Repositories ││ Project metadata │└──────────────────────────┘ Core Idea Behind […]
- [Understanding Indexes in AEM](https://stacknowledge.in/blogs/aem-indexes-query/): Adobe Experience Manager (AEM) uses the Apache Jackrabbit Oak repository as its underlying content storage and query engine. Unlike its predecessor Jackrabbit 2, Oak does not index content by default. This design prioritizes storage optimization and flexible indexing but also means developers must explicitly create indexes for efficient queries. Without well‑defined indexes, Oak may need to traverse large numbers of nodes, resulting in slow or unpredictable query performance. Understanding and configuring indexes is therefore essential for any scalable AEM implementation. Why Indexing Matters in Oak In Oak: Thus, indexes in Oak act like indexes in relational databases: They speed up queries […]
- [AEM Migration from On‑Prem to AEM as a Cloud Service (AEMaaCS)](https://stacknowledge.in/blogs/aem-migration-on-prem-aemaacs/): Migrating from AEM 6.x (on‑prem/AMS) to AEM as a Cloud Service is not a lift‑and‑shift. It’s a modernization journey that touches architecture, code, content, operations, and teams. This guide consolidates the end‑to‑end approach—including what’s changed in AEMaaCS, how to remediate those changes, and a phased methodology (Readiness → Implementation → Go‑Live → Optimization). It also maps Adobe’s official tools (BPA, CAM, Modernization suite, Repository Modernizer, Asset Workflow Migration, Dispatcher Converter, Index Converter) to practical steps. What’s Different in AEMaaCS (and Why It Matters) Below are the notable changes you must account for when migrating, with concrete actions to handle each. a) […]
- [AEM: Sling Framework](https://stacknowledge.in/blogs/aem-sling-framework/): Understanding Sling Resource Resolution, Sling Models, Exporters, and Sling Jobs The Apache Sling framework forms the core of request handling in Adobe Experience Manager (AEM). It introduces a powerful, resource‑centric approach for resolving requests, mapping URL structures, building models, exporting content as JSON, and processing asynchronous tasks through jobs.This article breaks down four major Sling concepts: Sling Resource Resolution Framework In Sling, everything is a resource. When a request comes in, Sling evaluates the URL and maps it to the best possible matching resource inside the repository. To do this, Sling decomposes the URL into distinct logical parts. URL Decomposition Consider […]
- [AEM Frontend Stack - Granite & Coral UI](https://stacknowledge.in/blogs/aem-frontend-granite-coral/): A practical, end‑to‑end guide to AEM’s frontend stack—Granite (Touch UI foundation) and Coral UI—with copy‑pasteable examples for dialogs, custom widgets, authoring forms/pages, and client libraries (categories, dependencies, embed, allowProxy). Focused on patterns that work cleanly in AEM 6.5 and AEM as a Cloud Service. Granite vs Coral UI (and where “Touch UI” fits) Granite in practice: dialogs, layouts & datasources A minimal Touch UI dialog field (server‑side Granite) Granite’s server components live at /libs/granite/ui/components/coral/foundation/** and expose standard form fields (textfield, select, datepicker, checkbox, etc.). Using a Granite DataSource to populate a Select dynamically Your /apps/stacknowledge/components/datasource/countries (Sling script/servlet) returns a DataSource of […]
- [Spring Boot ControllerAdvice: A Complete, Practical Guide](https://stacknowledge.in/blogs/spring-boot-controlleradvice-a-complete-practical-guide/): What Is @ControllerAdvice? @ControllerAdvice is Spring’s mechanism for applying cross-cutting concerns to multiple controllers—primarily global exception handling, but also data binding and model attributes. It lets you: Use @RestControllerAdvice for APIs (JSON responses), and @ControllerAdvice for MVC (views/templates). Basic Functionality & How It Works When a controller throws an exception, Spring MVC searches for an @ExceptionHandler method that can handle its type. If such a method is found in an applicable @ControllerAdvice (or the controller itself), it’s invoked to create the HTTP response (for REST) or render an error view (for MVC). @RestControllerAdvice vs @ControllerAdvice     Best for REST—handlers return serialized bodies […]
- [NGO and CSR: Philanthropy or Fraud?](https://stacknowledge.in/blogs/ngo-and-csr-philanthropy-or-fraud/): For decades, the concept of giving was simple: those who had plenty helped those who had little. Today, that simplicity has been replaced by a complex, multi-billion dollar industry where the lines between “non-profit” and “high-profit” are increasingly blurred. While the intention behind NGOs and Corporate Social Responsibility (CSR) is noble, a growing “philanthro-cynicism” suggests that these systems have evolved into legal machines used for tax evasion, money laundering, and maintaining elite lifestyles—a shadow economy. The NGO Loophole: From Grassroots to “Black-to-White” Pipelines While the majority of NGOs perform life-saving work, the sector’s lack of rigorous, real-time oversight has made it […]
- [AEM MSM: Multilingual & Multichannel with Custom Rollout](https://stacknowledge.in/blogs/aem-msm-multilingual-multichannel-with-custom-rollout/): 1) What is MSM and why it matters AEM Multi‑Site Manager (MSM) lets you build a single source (a Blueprint) and produce multiple Live Copies for different markets, regions, brands, or channels. You gain centralized control over structure and shared content, while still allowing local teams to make controlled changes. Typical goals you can achieve: 2) Multilingual (i18n) + Multichannel (Blueprint → LiveCopy) Multilingual with i18n Multichannel with Blueprints Build a Blueprint (for example /content/site/blueprint) that contains: Create Live Copies from the blueprint for each channel and region, e.g.: Each Live Copy inherits from the blueprint and can receive rollouts on […]
- [AEM: OSGi Components and Services](https://stacknowledge.in/blogs/aem-osgi-component-service/): OSGi (Open Service Gateway Initiative) provides a powerful Java framework for building modular, dynamic, and maintainable applications. Modern platforms like Adobe Experience Manager (AEM) leverage OSGi extensively—via the Apache Felix implementation—to create a flexible, service-oriented architecture. In this environment, developers can install, update, and remove modules at runtime without restarting the system. This article breaks down OSGi fundamentals—including bundles, components, and services—and uses practical examples to explain how they interact. What Is OSGi? OSGi provides both a modular system and a service platform for Java. It consists of two major parts: 1. Bundle Specification (Modularization Layer) OSGi applications are packaged as […]
- [AEM Link Checker & Transformer](https://stacknowledge.in/blogs/aem-link-checker-transformer/): Broken or incorrect links directly impact user experience, SEO, and content quality. AEM Link Checker is a built‑in capability that helps authors and developers automatically validate and manage links authored on pages and transform them if needed. Link Checker works in an event‑based manner—whenever content is created or updated under /content, link validation is triggered and the results are stored under /var/linkchecker. What Is AEM Link Checker? AEM Link Checker is responsible for: How Link Checker Works (High‑Level Flow) Internal vs External Links Internal Links External Links Author vs Publish Behavior Broken Links on Author Both internal and external broken links […]
- [Refetching Dispatcher Flush in AEM: A Smarter Caching Strategy](https://stacknowledge.in/blogs/refetching-dispatcher-flush-agent-aem-strategy/): Caching plays a critical role in ensuring high performance and scalability in Adobe Experience Manager (AEM) architectures. The Dispatcher sits between the Publish tier and end users, caching rendered content to reduce load on the Publish instances. However, how cache invalidation is handled can significantly impact system stability—especially during traffic spikes. This article explains the concept of refetching Dispatcher flush agents, why they are needed, how they work, and when they should (and should not) be used. The Problem with Plain Dispatcher Flush Agents A standard (plain) Dispatcher flush agent invalidates cached content when a page or asset is activated. Once […]
- [AEM: Showcasing Dynamic Content](https://stacknowledge.in/blogs/aem-dynamic-content-sdi-spa-cache/): Adobe Experience Manager (AEM) is widely used for building high‑performance, content‑driven websites where caching via Dispatcher and CDN plays a crucial role. However, not all content is static in nature. Use cases like user‑specific data, frequently changing widgets, real‑time notifications, or externally driven content require dynamic rendering strategies. This article explores three commonly used approaches to showcase dynamic content in AEM, explaining how each works, where it fits best, and the trade‑offs involved. 1. Sling Dynamic Include (SDI) What is Sling Dynamic Include? Sling Dynamic Include (SDI) is an AEM feature that allows specific components on an otherwise cacheable page to […]
- [Singleton Advanced: Risk & Fixes](https://stacknowledge.in/blogs/singleton-advanced-risk-fixes/): Double-Checked Locking In the previous example, using synchronized on the entire getInstance() method works, but it’s expensive. Every time a thread asks for the instance, it has to wait in line, even after the instance has already been created. To solve this Double-Checked Locking pattern is the “gold standard” for high-performance Singletons in multi-threaded environments. Double-checked locking solves this by only locking the first time. To do this correctly, you must use the volatile keyword. This ensures that multiple threads handle the instance variable correctly as it is being initialized. Why the “Double” Check Matters? The Role of volatile In Java, […]
- [The Loneliest Pattern: A Deep Dive into the Singleton](https://stacknowledge.in/blogs/singleton-design-pattern/): In the world of software engineering, there are times when “the more, the merrier” is exactly the wrong philosophy. Sometimes, you need exactly one—and only one—instance of a class to coordinate actions across a system. Enter the Singleton Design Pattern. What is the Singleton Pattern? The Singleton is a creational design pattern that ensures a class has only one instance while providing a global access point to that instance. Think of it like the “Government” of your application; there might be many departments, but there is only one central authority that everyone refers to. Why Use It? The primary driver for […]
- [React: Fetch a Binary Image with Axios and Display It as Base64](https://stacknowledge.in/blogs/react-axios-secured-binary-image/): In previous article, we integrated request headers (like an authentication token) into an axios instance for a React TypeScript application.In this follow‑up, we’ll see how to fetch binary data (an image) from the backend and convert it to a Base64 string that can be used directly in an <img> tag. Our scenario: we want to fetch a user’s profile image from a backend endpoint that returns the image as an ArrayBuffer, convert it to a Base64 string, and set it on component state to render the image. 1) State to hold the Base64 image We’ll store the image as a Base64 […]
- [Containerization: Deep Dive into Linux Cgroups and Namespaces](https://stacknowledge.in/blogs/containerization-linux-cgroups-namespaces/): In our previous article, we explored the evolution of deployment strategies—from physical machines to virtual machines (VMs) and finally to containerization. We established that containers are lightweight, scalable units that share the host’s operating system. But how exactly does that work? When people talk about containers, they almost immediately think of Docker. While Docker is the company that popularized the technology and made it accessible, they didn’t invent the underlying concept. The truth is, containers are purely a Linux concept that existed long before Docker. Docker simply built excellent tooling on top of existing Linux primitives. To understand containers, you have […]
- [Sling Content Distribution (SCD): a practical guide for cloud & on‑prem](https://stacknowledge.in/blogs/sling-content-distribution/): Apache Sling Content Distribution (SCD) lets you move content (Sling resources) across Sling/AEM instances using a path‑level API and configurable distribution agents. It works equally well on classic on‑prem topologies and in modern cloud deployments (including AEM as a Cloud Service), where publishing is powered by SCD under the hood. [sling.apache.org], [sling.apache.org], [experience….adobe.com] [stacknowledge.in] What SCD is (and why it matters) If you’re targeting very large cloud topologies, the Journal‑based SCD implementation offers cloud‑friendly scale using a persisted log and shared blob store for large binaries (binary‑less packages). Architectural building blocks Distribution scenarios 1) Forward distribution (push) Push content from a […]
- [The Flagship Trap: Why Your New Phone Is Designed to Feel Old by This Time Next Year](https://stacknowledge.in/blogs/the-flagship-trap-new-phone-designed-feel-old-by-this-time-next-year/): Have you ever unboxed a brand-new, $1,200 flagship smartphone, only to feel like it belongs in a museum just twelve months later? According to research, this common consumer experience is known as the “Billion-Dollar Heartbreak.” Although it feels like an accident, smartphone manufacturers intentionally build this dynamic into the tech ecosystem. If you want to understand how tech companies keep you upgrading, you must look closely at how they price their hardware, manage their software, and manipulate consumer psychology. Breaking Down the Real Cost of Your Phone When you purchase a flagship device on launch day, you pay far more than […]
- [File Uploads and Retrieval in Spring Boot](https://stacknowledge.in/blogs/spring-java-file/): In contemporary web development, the ability to seamlessly manage file uploads and downloads has transitioned from a specialized feature to a fundamental core requirement. Whether you are building an enterprise document management system, a social media platform, or a simple profile-update service, mastering binary data handling is essential for any robust backend. This article provides a deep dive into implementing these critical features within the Spring Boot ecosystem. We adopt a “core-to-shell” architectural approach: we begin at the foundational layer by mastering Java NIO (New I/O) operations for efficient file system interaction. From there, we build outward, wrapping those low-level operations […]
- [React Authentication: Securing Your APIs with Axios](https://stacknowledge.in/blogs/auth-calls-axios-react/): When building a React application, Axios is a popular choice for managing HTTP requests. It works seamlessly with mock APIs during development, but challenges often arise when connecting to a real backend server. One common issue is receiving 403 Forbidden errors because the server requires a bearer token in the request header. The Problem During development with mock responses, GET, POST, PUT, and DELETE calls may run smoothly. However, once connected to a live backend, requests can fail if they lack proper authentication headers. In many cases, the backend expects a bearer token to validate the client. The Solution: A Common […]
- [Caching Strategies for Dispatcher & CDN in Dynamic AEM Environments](https://stacknowledge.in/blogs/caching-for-dispatcher-cdn-with-dynamic-aem-data/): How to ensure fast, reliable, selective cache updates when Content Fragments (CF) and Experience Fragments (XF) change Modern AEM implementations rely heavily on caching to deliver high‑performance digital experiences. Dispatcher (the AEM cache layer) and Content Delivery Networks (CDNs) together accelerate content delivery and reduce compute load on Publish instances. However, when dynamic content like Content Fragments (CFs) and Experience Fragments (XFs) change, any page rendering those items must be refreshed, or users will see stale data. This article outlines a robust strategy—aligned with business requirements—to handle cache invalidation efficiently across Dispatcher and CDN layers. Why Caching Is Complex for CFs […]
- [AEM Replication & Dispatcher Flush: Agents & Sling Content Distribution](https://stacknowledge.in/blogs/aem-replication-flush-agent-sling-content-distribution/): Replication Agents: what they do & where they live Replication agents in AEM are the mechanism to: They are configured in the repository and via classic admin UIs: A development environment can have multiple cq-author and cq-publish instances, so an Author can have many agents, each targeting one or more Publish instances. Forward Replication (Author → Publish) Example: Create a Publish Replication Agent under /etc/replication You can create this under /etc/replication/agents.author for the Author runmode (CRXDE Lite). The node types and properties matter. /etc/replication └── agents.author └── publish_4503 (sling:Folder) ├── jcr:content (cq:PageContent) │ ├── enabled = true │ ├── serializationType = […]
- [Builder Design Pattern vs Chain of Responsibility Pattern](https://stacknowledge.in/blogs/builder-design-pattern-vs-chain-of-responsibility-pattern/): Both patterns belong to the Gang of Four (GoF) design patterns but serve different purposes: Builder Design Pattern Builder Pattern separates the construction of a complex object from its representation, allowing the same construction process to create different representations. Structure Where to Use Drawbacks Chain of Responsibility Pattern Allows a request to be passed along a chain of handlers. Each handler decides whether to process the request or pass it to the next handler. Structure Where to Use Drawbacks Similarities Differences Aspect Builder Pattern Chain of Responsibility Pattern Purpose Object creation Request handling Category Creational Behavioral Output A fully built object […]
- [Factory Design Pattern vs Abstract Factory Design Pattern](https://stacknowledge.in/blogs/factory-design-pattern-vs-abstract-factory-design-pattern/): Creational design patterns help developers handle object creation cleanly. Instead of scattering the new keyword throughout your application, these patterns centralize your instantiation logic. Two of the most common creational patterns are the Factory Method Pattern and the Abstract Factory Pattern. While they sound incredibly similar, they serve entirely different structural purposes. This article breaks down their core differences, architectural layouts, real-world use cases, and code implementations. What is the Factory Design Pattern? The Factory Method pattern defines an interface or an abstract class for creating a single object, but it lets subclasses decide which specific class to instantiate. Consequently, it […]
- [Cluster-aware event handling in AEM: using TopologyEventListener and topology-aware jobs](https://stacknowledge.in/blogs/cluster-aware-event-handling-in-aem-using-topologyeventlistener-and-topology-aware-jobs/): Why “cluster‑aware” matters in AEM (especially Cloud Service) On AEM as a Cloud Service, code always runs in a cluster, instances are ephemeral, and leader election can be in progress when events fire. Your background work must tolerate restarts and resume reliably. If you need a single “primary” to act, use Apache Sling Discovery to identify the leader. [Reference link] Apache Sling Discovery models your deployment’s topology (instances ↔ clusters). Key types: You obtain the current view via DiscoveryService#getTopology(). [sling.apache.org] The legacy Granite/JCR ClusterAware interface is deprecated—replace it with TopologyEventListener. [developer.adobe.com] Quick recap: event options you covered previously TopologyEventListener: reacting to […]
- [Java Memory Management Explained: Heap, Stack, and Garbage Collection](https://stacknowledge.in/blogs/java-memory-management-explained-heap-stack-and-garbage-collection/): Java applications rely heavily on efficient memory management to ensure performance and stability. Understanding how memory is allocated and managed is crucial for developers working on large-scale applications like AEM. JVM Memory Parameters When starting an AEM instance, you often see commands like: Key Parameters -XX:MaxPermSize=256m Sets the maximum size for the Permanent Generation (PermGen) heap. -Xmx1024M : Sets the maximum Java heap size (where objects live). -Xms : Sets the Initial heap size. -Xss : Sets Stack size per thread Heap vs Stack Memory Heap Memory Stack Memory Garbage Collection (GC) Java automatically manages memory using Garbage Collection: Types of […]
- [AEM Component Placement Strategies: Overlay, Override, and Resource Merge](https://stacknowledge.in/blogs/aem-component-placement-strategies-overlay-override-and-resource-merge/): Adobe Experience Manager (AEM) gives you three core patterns to place and customize components safely and upgrade‑friendly: Overlay, Override, and Resource Merge. Choosing the right strategy depends on what you want to change (UI, dialog, rendering, configuration), how broadly the change should apply, and whether you need inheritance or a full copy. This article explains each approach, how it appears to authors (e.g., in Sidekick/Component Browser), plus best practices and pitfalls – especially for AEM 6.5 and AEM as a Cloud Service. Quick definitions 1) Overlay What it is — Overlaying means duplicating the node structure from ‘/libs’ to ‘/apps’ at […]
- [React Hooks: useEffect, useCallback, useMemo, and useRef - When & How to Use Them](https://stacknowledge.in/blogs/react-hooks-useeffect-usecallback-usememo-and-useref-when-how-to-use-them/): React Hooks let function components manage state and side effects while keeping code concise and composable. This article focuses on when to use each hook and how to structure them for readability and performance. useEffect: Side Effects (after render) with Optional Cleanup Use ‘useEffect’ whenever you have side effects – logic that must run after React has painted changes to the DOM or after state/props change. Typical effects include fetching, subscribing, logging, updating document title, and imperative DOM interaction. Patterns 1) Effect reacting to a particular state change 2) Effect on mount/unmount only (no dependencies) ‘useEffect’ does not run before the […]
- [Run Modes in AEM: Configuration and Best Practices](https://stacknowledge.in/blogs/run-modes-in-aem-configuration-and-best-practices/): Adobe Experience Manager (AEM) uses Run Modes to define environment-specific behavior. They allow you to load configurations, enable bundles, and apply settings tailored for development, staging, or production without duplicating code. Out-of-the-Box Run Modes AEM provides several default run modes: Important: Setting Run Modes (Precedence Order) AEM determines active run modes based on the following precedence: 1. sling.properties file Located at: /crx-quickstart/conf/sling.properties Example: sling.run.modes=author,stages 2. The ‘-r’ option during startup Example: java -jar cq-6-p4502.jar -r stage 3. System property in start script Example: -Dsling.run.modes=publish,prod 4. Filename detection AEM can infer run modes from the quickstart JAR filename: cq-author-p4502.jar 5. Defining run […]
- [Understanding Templates in AEM: Static vs Editable](https://stacknowledge.in/blogs/aem-templates-static-editables/): Templates in Adobe Experience Manager (AEM) control the structure, policies, and component availability for pages. Broadly, AEM supports two kinds of templates: This guide covers both, along with how to create, configure, and use them, and lists all relevant properties you’ll encounter, including Allowed Paths, Children, Parent, Policies, Layout Container options, and more. 1) Static Templates Static templates are repository nodes under /apps (or /libs) that define a fixed page structure using JSP/HTL includes. They are owned by developers, and changes require code deployment. Typical Structure When to Use Creation 2) Editable Templates Editable templates are created and managed in AEM’s […]
- [AEM Event Handling at a Glance](https://stacknowledge.in/blogs/aem-event-handling-at-a-glance/): This guide consolidates AEM event-handling approaches with what each mechanism does, when to use them, how to implement, and copy-paste code samples. Designed for day-to-day development and operations. AEM exposes several event mechanisms, each suited to a different layer: When to Use Which EventHandler – Decoupled intra-app communication (domain events).JCR EventListener – Precise, path-scoped detection of node/property changes.ResourceChangeListener – Sling-native resource events with glob/path filtering.Sling Jobs – Offload heavy/Retryable work with backoff and cluster-aware processing.Workflow Launchers – Business processes (multi-step, approvals) started by repository changes.TransportHandler – Custom replication transport to external systems (CDN/API/message bus). 1) OSGi Event Admin – EventHandler What […]
- [Spring Boot Annotations in a Nutshell](https://stacknowledge.in/blogs/java-spring-boot-annotations-nutshell/): Spring Boot builds on Spring to let you create production-grade applications with minimal configuration. Annotations drive most of the functionality – component scanning, dependency injection, configuration, web endpoints, persistence, security, caching, scheduling, and testing. Read more about them in this blog. Application Bootstrap & Configuration @SpringBootApplication What it is: Convenience annotation that combines @Configuration, @EnableAutoConfiguration, and @ComponentScan.Use when: Bootstrapping your application. @Configuration+@Bean What they do: Define configuration classes and factory methods for Spring-managed beans.Use when: You need fine-grained control over bean creation or third‑party library wiring. @Value and @ConfigurationProperties What they do: Bind properties to fields.Use when: Injecting configuration values (URLs, […]
- [Java: Project Lombok](https://stacknowledge.in/blogs/java-project-lombok/): What it is, why it helps, and how to use its most useful annotations in everyday Java coding. It’s designed to be copy-paste ready with examples you can drop into your projects. What is Lombok and Why Use It? Project Lombok is a Java library that reduces boilerplate code by generating common methods (getters, setters, constructors, builders, logging, etc.) at compile time. It makes code cleaner, more readable, and faster to write, especially in domain-driven and Spring-based applications. Setup (Maven/Gradle + IDE) Maven Gradle IDE Core POJO Annotations 1) @Getter / @Setter Generates getters and/or setters for fields. Tips 2) @ToString […]
- [High-Rise Apartments: Economy vs. Nature](https://stacknowledge.in/blogs/high-rise-apartments-economy-vs-nature/): Modern skylines are dominated by towering high-rise apartments – symbols of progress, luxury, and urban ambition. For many, living in these buildings is a dream come true: waking up to panoramic views, feeling above the crowd, and enjoying the convenience of city life. But behind this glittering façade lies a critical question: Are high-rise apartments truly sustainable, or are they silently eroding our natural balance? Why High-Rises Exist High-rise apartments are often born out of necessity. In densely populated cities where land is scarce and demand for housing is high, vertical expansion becomes the most viable solution. Economically, these structures make […]
- [React Redux: Middleware to manage side effects with generators](https://stacknowledge.in/blogs/redux-saga-thunk-middleware/): As we discussed in a previous post, Redux is synchronous by nature. To handle asynchronous operations – such as making API calls – it requires the use of middleware. While Redux Thunk and Redux Saga are among the most popular choices for middleware, we are going to dive deeper into them here. To recap, Redux is a centralized and predictable state container for JavaScript applications. It acts as a single source of truth, making state management easier to maintain. With its strong community support, extensive documentation, and vast ecosystem, Redux remains a staple in modern web development.One of its most popular […]
- [AEM: Sightly Dialog Validation](https://stacknowledge.in/blogs/aem-sightly-dialog-validation/): In Adobe Experience Manager (AEM), a Sightly dialog (based on the cq:dialog node) can include various structural nodes such as panels and tabs. Within these structures, you can add input components like text fields, dropdowns, and radio buttons.This guide explains how to implement basic custom validation for these dialog fields. Step 1: Create a Client Library Create a client library under your component’s main folder with the following properties: Step 2: Add JavaScript for Validation Create a JavaScript file in the clientlib folder and implement your validation logic. There are multiple approaches: Option 1: Validation Attribute Option 2: Foundation Validation API […]
- [AEM: OIDC based Custom Authentication Handler](https://stacknowledge.in/blogs/aem-oidc-based-custom-authentication-handler/): OpenID Connect or commonly known as OIDC is an authentication layer on top of the OAuth 2.0 authorization framework. It allows computing clients to verify the identity of an end user based on the authentication performed by an authorization server, as well as to obtain the basic profile information about the end user in an interoperable and REST-like manner. In technical terms, OpenID Connect specifies a RESTful HTTP API, using JSON as a data format. We covered 3 scenarios which we came accross while doing a POC for Microsoft’s OIDC based login with AEM. You can also check this link on […]
- [Redux: ReactJS via HOC & Hooks](https://stacknowledge.in/blogs/redux-reactjs-via-hoc-hooks/): Redux as we know is the global state manager, which can be used with Javascript or Typescript.We know the basic implementation behind the redux with – redux-vanilla-javascript There’s an official React-Redux package by redux to implement it with ReactJS. The package is optimized to minimalize the component re-rendering, it only happens when data used by component changes. Before React 16.8, only way of connecting React Component to Redux store is via High-order components (HOC)connect() function connects a React component to a Redux store, it requires developer to define which data component needs from the store and which functions are available to […]
- [Containerization: Introduction](https://stacknowledge.in/blogs/containerization-introduction/): In the modern era of DevOps and cloud computing, containerization has emerged as a revolutionary technology, solving the age-old problem of ‘it works on my machine‘ by ensuring applications run seamlessly across any environment. Traditional Model Initially we used to have this traditional model where we have physical machines with OS on top of that and we are just installing out application along with all the libraries and so on. But thiese physical machine is not being used in efficient manner and also there’s some limitation like kernel structure for example if my machine is Windows machine than we can’t run […]
- [AEM: Content fragments with GraphQL](https://stacknowledge.in/blogs/aem-content-fragments-with-graphql/): Adobe Experience Manager (AEM) has evolved into a powerful headless CMS by decoupling content creation from the presentation layer. At the heart of this architecture are Content Fragments, which allow you to design, create, and manage structured, channel-neutral content. To retrieve this data efficiently for modern front-end frameworks like React, Angular, or mobile apps, AEM leverages GraphQL. Unlike traditional REST APIs, the AEM GraphQL API enables developers to query specific data structures, reducing payload size and providing a flexible, “self-documenting” way to consume content. By utilizing Content Fragments with GraphQL, organizations can ensure a “create once, publish everywhere” strategy while maintaining […]
- [Redux: Vanilla JavaScript](https://stacknowledge.in/blogs/redux-vanilla-javascript/): Though redux have lots of features, you can read about all of them here but main feature because of which everyone is using Redux is that it can be very useful to manage state of the application at global level. It can be used with any JavaScript or TypeScript code. It keeps our state container centralized and predictable for our JavaScript Apps. Side Effect: Redux is synchronous by nature and if you want to make async call requests like an API call, redux need additional middlewares. Some of the popular middleware are Redux Thunk and Redux Saga. Lets try to setup […]
- [Spring Security: Custom Authencation with OTP based login](https://stacknowledge.in/blogs/spring-security-custom-authencation-with-otp-based-login/): We will walk through you on how to setup Spring Security with Custom Authentication handler for OTP based login. We are going to use JWT for authentication which will be pass in request header as authorization bearer token. Prerequisites: You must be familiar with Java & Spring Framework to understand it. First you need to set up the project for which you can use https://start.spring.io/, for this demo I have used 3.5.6 version along with Java 21. You need to add these basic dependencies: Configure your database, you can use the steps mentioned here to setup your database connection and create […]
- [Spring: Database connection with MySQL](https://stacknowledge.in/blogs/spring-database-connection-with-mysql/): This is a walkthrough for establishing a connection between backend java code and database using spring boot. First you need to set up the project for which you can use https://start.spring.io/, in this demo I have used 3.5.6 version of Spring Boot along with Java 21. Add dependencies to your project based on your requirements. I am going to use JPA Repository to handle all my database related interactions and MySql as database. This is how my POM looks like: Create an entities for your tables, following are the samples with relation to one another. To learn about what kinds of […]

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