Focused on Java interview questions and practical article sharing, covering algorithms, databases, Spring Boot, microservices, high concurrency, JVM, Docker containers, and ELK-related knowledge. Looking forward to progressing together with you.
This article explains IPv6 fundamentals, compares it with IPv4 across address length, header format, security and configuration, and provides interview‑ready insights such as SLAAC auto‑configuration, dual‑stack transition, and common follow‑up questions.
The article explains how CDN works as a distributed reverse‑proxy cache, details its DNS‑based load balancing, cache‑hit/miss flow, expiration policies and refresh strategies, compares CDN caching with browser and Nginx caches, outlines scenarios where CDN or Redis is appropriate, and provides typical interview follow‑up questions and practical tips.
The article breaks down the complete browser workflow from URL entry to page rendering, covering URL parsing, DNS lookup (recursive and iterative), TCP three‑way handshake, TLS negotiation, HTTP request/response exchange, and the final rendering steps, while also providing interview‑focused Q&A and a memorization mnemonic.
The article explains that Young GC fires when the Eden space is full, while Full GC can be triggered by old‑generation shortage, metaspace exhaustion, allocation‑guarantee failure, or an explicit System.gc() call, and provides interview‑ready answers, diagnostic steps, and a comparison table.
The article explains why RabbitMQ may deliver the same message multiple times, emphasizes that business‑level idempotency is required, and compares five concrete deduplication approaches—unique message ID with a dedup table, database unique constraints, Redis SETNX, optimistic locking, and state‑machine design—detailing their implementation, suitable scenarios, and trade‑offs.
The article explains that TCP's byte‑stream nature causes sticky and unpacked packet problems, analyzes why they occur, compares UDP, and presents four application‑layer solutions—especially the Header‑Body length‑field approach used by Netty—providing code examples and interview‑ready answers.
The article explains four ways to preheat caches in Spring during startup, recommends CommandLineRunner/ApplicationRunner as the safest option, and discusses timing, async handling, error protection, and distributed‑lock strategies to avoid common pitfalls in production environments.
The article breaks down RabbitMQ's three‑stage message flow—producer to broker, broker persistence, and broker to consumer—detailing how Publisher Confirm, durable exchanges/queues/messages, and manual consumer acknowledgments together guarantee reliability while discussing performance trade‑offs, high‑availability clustering, and common interview follow‑up questions.
The article explains why Full GC should be minimized, defines normal versus abnormal GC frequencies, outlines the root causes of Full GC, and provides a step‑by‑step troubleshooting workflow with concrete code snippets, monitoring commands and real‑world examples for Java backend engineers.
The article explains that a daemon (background) thread in Java supports user threads but does not prevent JVM shutdown; when all non‑daemon threads finish, the JVM exits regardless of daemon threads, covering definitions, usage scenarios, creation methods, pitfalls, detailed comparisons, and typical interview questions.
