Every Java concept explained in depth — from variables to multithreading, Spring Boot, JDBC, Microservices, and Design Patterns.
public class Main { public static void main(String[] args) { // Java 21 – Virtual Threads var greeting = "Welcome to Java! 🚀"; System.out.println(greeting); for (int i = 1; i <= 5; i++) { System.out.println("Step " + i + " ✓"); } } }
Click any topic to dive in with full explanations and programs
History, features, JVM/JDK/JRE, platform independence
Install JDK, compile & run, program structure
Primitives, type casting, literals, var keyword
Arithmetic, relational, logical, bitwise, ternary
Conditional logic, nested if, switch expressions
for, while, do-while, for-each, break, continue
1D & 2D arrays, sorting, searching, Arrays class
Class anatomy, object creation, methods, static members
Default, parameterized, copy constructor, this keyword
extends, super keyword, method overriding, types
Overloading, overriding, dynamic dispatch, instanceof
Abstract classes, abstract methods, design patterns
Access modifiers, getters/setters, data hiding
interface keyword, default methods, functional interfaces
String methods, StringBuilder, StringBuffer, regex
try-catch-finally, custom exceptions, checked/unchecked
List, Set, Map, Queue, Iterator, Comparable
Generic classes, methods, wildcards, bounded types
Lambda expressions, Stream API, filter, map, reduce
Thread class, Runnable, synchronization, ExecutorService
File class, streams, BufferedReader, NIO, serialization
Lambdas, Streams, Optional, Date/Time API, default methods
Records, Sealed classes, Text Blocks, Pattern Matching
Virtual Threads, Record Patterns, Sequenced Collections
Value Classes, Stream Gatherers, Structured Concurrency
Connections, PreparedStatement, ResultSet, transactions, pooling
IoC container, Dependency Injection, Beans, AOP
Auto-configuration, starters, Actuator, REST API
Controllers, REST APIs, request mapping, validation
JPA entities, Hibernate ORM, JpaRepository, JPQL
Architecture, Eureka Service Discovery, API Gateway, Feign, Resilience4j
Singleton, Factory, Builder, Observer, Strategy, Proxy, Template Method with Spring
Saga, CQRS, Outbox, API Gateway, Circuit Breaker, Service Mesh, Sidecar, CDC, and more
From writing test cases and bug reports to Selenium, TestNG, BDD Cucumber, API testing, Playwright, Tosca, and CI/CD pipelines.
@Test public void loginTest() { driver.get("https://app.example.com"); driver.findElement(By.id("username")).sendKeys("admin"); driver.findElement(By.id("login")).click(); Assert.assertEquals(driver.getTitle(), "Dashboard"); }
Comprehensive manual testing, framework development, and automation engineering
SDLC, STLC, testing levels, quality assurance fundamentals
Black box, white box, regression, sanity, smoke testing
Boundary value analysis, equivalence partitioning, state transition
Defect statuses, severity vs priority, Jira bug reporting
Locators, dynamic waits, popups, frames, actions class
Annotations, assertions, parallel testing, DataProviders
Design pattern, PageFactory, framework structure
HTTP methods, Postman, RestAssured BDD assertions
Gherkin syntax, Feature files, Step Definitions, Hooks
Jenkins integration, Maven surefire,ExtentReports
AI test generation, self-healing locators, test analytics
Auto-waiting, multi-tab contexts, network mocking
Model-based test automation, Modules, TestCases, Execution Lists
From TypeScript fundamentals and components to RxJS, Reactive Forms, Routing, Material Design, and NgRx state management.
@Component({ selector: 'app-root', template: `<h1>{{ title }}</h1>` }) public class AppComponent { title = 'Angular App 🚀'; }
Build robust, scalable enterprise single-page applications
Architecture, Angular CLI, project structure, modules
Types, interfaces, classes, generics, decorators
Component lifecycle, inline vs external templates, styles
Interpolation, property, event, two-way binding, ngIf, ngFor
Injectable, singleton services, hierarchical injectors
RouterModule, route parameters, guards, lazy loading
FormBuilder, FormGroup, FormControl, custom validators
HttpClient, Observables, Subjects, RxJS operators
Built-in pipes, custom pipes, pure vs impure pipes
Angular Material UI, NgRx store, actions, reducers, effects
From JSX and Functional Components to Hooks, React Router, Context API, Redux Toolkit, and React Testing Library.
function App() { const [count, setCount] = useState(0); return ( <button onClick={() => setCount(count + 1)}> Count: {count} </button> ); }
Build modern, reactive UIs with React Hooks, Redux Toolkit, and React Router
What is React, CRA/Vite setup, JSX basics, Virtual DOM
Functional components, class components, component tree
Passing data, useState, lifting state, controlled components
SyntheticEvents, forms, list rendering, keys
useState, useEffect, cleanup, dependency array
useContext, useReducer, useMemo, useCallback, useRef
BrowserRouter, Routes, Link, useNavigate, dynamic routes
fetch, Axios, async/await, loading states, error handling
Store, slices, createAsyncThunk, useSelector, useDispatch
Jest, React Testing Library, mocking, snapshot testing
Comprehensive, real-world technical interview questions and expert answers for Core Java, Spring Framework, Spring Boot, and Microservices architecture.
// Key Technical Q&A Guides public class InterviewPrep { public static void main(String[] args) { System.out.println("1. Core Java Interview Q&A"); System.out.println("2. Spring Framework Interview Q&A"); System.out.println("3. Spring Boot Interview Q&A"); System.out.println("4. Microservices Interview Q&A"); } }
Select any track to view comprehensive interview questions & answers
JVM, OOP, Collections, Multithreading, Exception Handling, Streams & Java 8-26
IoC Container, Dependency Injection, Bean Scopes, Lifecycle, AOP & Proxies
Auto-Configuration, Actuator, REST APIs, Exception Handling, Hibernate N+1
API Gateway, Eureka, Saga Pattern, CQRS, Outbox, Circuit Breaker, Tracing