28 docs tagged with "advanced"

The structure of Java .class files — constant pool, bytecode instructions, and using javap to disassemble compiled code — plus how generics erasure, lambdas, and string concatenation look at the bytecode level.

Consolidated interview Q&A for the Java Collections Framework — hierarchy, List, Set, Map, Queue, iterators, sorting, and immutability — from beginner through advanced.

Consolidated interview Q&A for Core Java covering beginner through advanced topics — variables, types, operators, control flow, arrays, strings, methods, and packages.

Core theory behind distributed systems — CAP theorem, consistency models, idempotency, and the Saga pattern for distributed transactions — for Java/Spring Boot backend engineers.

Scenario-based walkthrough of implementing a choreography-based Saga for an e-commerce order flow with idempotent Kafka consumers in Spring Boot.

Consolidated interview Q&A for Java Exceptions — hierarchy, try/catch/finally, custom exceptions, and best practices from beginner through advanced.

Consolidated interview Q&A for Java Functional Programming — lambdas, functional interfaces, method references, streams, collectors, parallel streams, and Optional.

Consolidated interview Q&A for GoF design patterns in Java — creational, structural, and behavioral — covering beginner through advanced topics.

How the JVM's Just-In-Time compiler converts hot bytecode into native machine code at runtime — tiered compilation (C1/C2), inlining, escape analysis, and the warmup behavior you see in every production service.

Deep dive into Java's Map implementations — how HashMap buckets work, when to use LinkedHashMap or TreeMap, and why ConcurrentHashMap is the thread-safe choice.

Hands-on examples for HashMap, LinkedHashMap, TreeMap, and ConcurrentHashMap — frequency counting, LRU cache, range queries, and atomic operations.

Consolidated interview Q&A for Java Multithreading — threads, synchronization, wait/notify, ExecutorService, locks, atomics, thread safety, and virtual threads from beginner through advanced.

Quick-reference summary of Java concurrency — threads, synchronization, locks, atomics, ExecutorService, CompletableFuture, virtual threads — for rapid revision.

Hands-on examples for OAuth2 and OpenID Connect in Spring Boot — social login, resource server with external auth server, client credentials for microservices, and accessing OIDC user info.

OAuth2 authorization flows, the resource server and authorization server patterns, OpenID Connect identity layer, and how to configure Spring Boot as an OAuth2 client and resource server.

When parallel streams improve throughput, when they hurt, and how the ForkJoin common pool governs parallel execution.

Hands-on examples demonstrating when parallel streams help, when they hurt, and common correctness pitfalls.

Horizontal vs vertical scaling, stateless services, read replicas, database sharding, and load balancing — the patterns that allow a Java/Spring Boot system to handle growing traffic.

Scenario-based walkthrough of making a Spring Boot service horizontally scalable — stateless sessions with Redis, connection pool tuning, read replica routing, and async offloading.

Hands-on code examples and step-by-step walkthroughs for Sealed Classes (Java 17+) in Java.

Restrict which classes can extend or implement a type — enabling exhaustive pattern matching and modeling closed, well-known type hierarchies safely.

Consolidated interview Q&A for Spring Framework covering IoC container, dependency injection, bean lifecycle, bean scopes, AOP, and Spring Events — beginner through advanced.

Consolidated interview Q&A for Spring Security covering filter chain, authentication, authorization, JWT, OAuth2, CSRF, and CORS — beginner through advanced.

Quick-reference summary of System Design concepts — SOLID, microservices, API design, caching, reliability patterns, distributed systems, and scalability — with top interview questions.

Hands-on walkthroughs of creating virtual threads, measuring scalability, detecting pinning, and using StructuredTaskScope.

Project Loom's virtual threads — how they work, how they remove the scalability ceiling of thread-per-request servers, and what pinning and structured concurrency mean for your code.

Hands-on Spring WebFlux examples covering Mono/Flux basics, annotated controllers, functional routing, parallel I/O with Mono.zip, and SSE streaming.

Spring WebFlux — the reactive, non-blocking alternative to Spring MVC — covering Mono, Flux, functional endpoints, backpressure, and when to choose reactive over the blocking model.