In SQL, CASCADE is an option used with FOREIGN KEY constraints when defining relationships between tables. It specifies that certain actions on a parent table should automatically propagate to the related child table(s). The most common use cases are ON DELETE CASCADE and ON UPDATE CASCADE. Let's break it down: 1. ON DELETE CASCADE…
A Time-Series Database (TSDB) is a type of database optimized specifically for storing, retrieving, and analyzing time-stamped data, i.e., data points indexed by time. This is common in monitoring systems, IoT sensors, finance, telemetry, and any system that generates data continuously over time. Unlike traditional relational databases, TSDBs are optimized for high write throughput…
WebRTC (Web Real-Time Communication) in JavaScript is a set of APIs and protocols that allows web applications to establish peer-to-peer (P2P) connections directly between browsers or devices. It enables real-time audio, video, and data sharing without requiring users to install plugins or external software. Here’s a clear breakdown: Key Features of WebRTC Real-time Audio…
WebSockets is a communication protocol that enables full-duplex, persistent connections between a client (like a web browser) and a server over a single TCP connection. Here’s a breakdown: Traditional HTTP is request-response based: the client sends a request, and the server responds, then the connection usually closes. WebSockets, on the other hand, keep the…
A Progressive Web App (PWA) is a type of web application that uses modern web technologies to deliver an experience similar to native mobile or desktop apps. PWAs are built with standard web technologies (HTML, CSS, JavaScript) but have enhanced capabilities like offline access, push notifications, installability, and fast performance. They’re called progressive because…
BasicsBasicsOverviewOverviewJava Learning roadmapJava Learning roadmapOOPOOPException handlingException handlingMulti threadingMulti threadingJava I/OJava I/OGenericsGenericsCollectionsCollectionsjava utilsjava utilsHistoryHistoryversionsversionsenvironnementenvironnementStandard Edition (SE)Standard Edition (SE)Enterprise Edition (EE)Enterprise Edition (EE)Micro Edition (ME)Micro Edition (ME)Wrapper classesWrapper classesPass by value referencePass by value referen...Methods overriding/overloadingMethods overriding/ov...Type CastingType CastingStringBuffer/StringBuilderStringBuffer/StringBuilderBasic interfacesBasic interfacesBasic ClassesBasic ClassesArraysArraysenumenumOperatorsOperatorsstatic final super thisstatic final super th...EncapsulationEncapsulationInheritanceInheritanceAbstractionAbstractionAccess ModifiersAccess ModifiersNested/Inner classNested/Inner classtype exceptionstype exceptionstry/catchtry/catchthrow throws…
Spring CoreSpring CoreSpring WebSpring WebArchituctural PatternArchituctural...Spring AOPSpring AOPSpring SecuritySpring SecuritySpring DataSpring DataSpring TestSpring TestSpring CloudSpring CloudSpring BatchSpring BatchSpring ShellSpring ShellObservabilityObservabilitySpring ReactiveSpring ReactiveInversion of ControlInversion of ControlDependency InjectionDependency InjectionService Locator PatternService Locator Patt...Event-driven AchitectureEvent-driven Achitec...Service DiscoveryService DiscoveryAPI GatewayAPI GatewayLoad BalancingLoad BalancingConfiguration ManagementConfiguration Manage...Resilience & Fault ToleranceResilience & Fault T...Distributed TracingDistributed TracingEvent-driven SystemsEvent-driven SystemsDistributed TasksDistributed TasksjdbcjdbcORMORMRelationalRelationalNoSQlNoSQlCacheCacheHibernateHibernateJPAJPASearch…
System Design Principles are the fundamental guidelines and best practices used to build scalable, maintainable, and reliable software systems. They help backend developers and architects make decisions about architecture, data flow, and infrastructure to handle real-world requirements like performance, reliability, and growth. Here’s a detailed breakdown: 1. Scalability Ability of a system to handle…
1. Array → Collection (List/Set) Java provides multiple ways to convert an array into a collection (usually a List or Set). ✅ Using Arrays.asList() import java.util.*; public class Main { public static void main(String[] args) { String[] array = {"Java", "Python", "C++"}; // Convert to List List<String> list = Arrays.asList(array); System.out.println(list); // [Java, Python,…
Java provides java.util.regex package with two main classes: Pattern → Compiles the regex. Matcher → Used to match patterns against text. Basic Example import java.util.regex.*; public class RegexExample { public static void main(String[] args) { String text = "My email is test@example.com"; String regex = "\\w+@\\w+\\.\\w+"; // Simple email regex Pattern pattern = Pattern.compile(regex);…