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 breaks down the QR code login process used by Douyin, explaining how the system identifies the user, proves their identity through a token‑based authentication flow, and details each step from QR generation to final confirmation on the PC side.
The article explains two ways to implement a 30‑minute order auto‑cancellation in RabbitMQ—using the classic TTL + dead‑letter exchange pattern (with its head‑blocking pitfall) and the newer delayed‑message‑exchange plugin—provides Spring Boot configuration examples, compares their trade‑offs, and offers interview tips on when to choose each solution.
The article explains the fundamental design flaws of java.util.Date, why a code‑scan rule forces its removal, and provides a step‑by‑step guide to replace Date and related utilities with the modern java.time API, including concrete code transformations and migration tips.
RabbitMQ achieves consumer‑side throttling by configuring basic.qos with a prefetchCount, disabling automatic ACK, and using manual ACK so that the broker only pushes a limited number of unacknowledged messages, with detailed guidance on parameter settings, pitfalls, and code examples.
This article walks through the core features of PowerJob, compares it with other Java job schedulers, and provides step‑by‑step instructions for installing, configuring, and creating tasks using both Docker and jar deployments, complete with code samples and UI screenshots.
This article explains the concept of RabbitMQ dead‑letter queues, the three conditions that turn a message into a dead letter, how to configure DLX and routing keys in Spring Boot, common pitfalls, a classic order‑timeout use case, and typical interview follow‑up questions.
The article outlines the evolution from isolated push modules to a unified framework and finally a dedicated push service, detailing functional and non‑functional requirements, component responsibilities, priority handling, and a scalable micro‑service architecture for enterprise notifications.
Hybrid search combines dense vector retrieval with sparse keyword search, using RRF fusion and optional reranking, to overcome the limitations of each method—semantic understanding versus exact matching—making it the production‑grade standard for RAG systems by 2025‑2026.
The article explains why a POST request can result in two HTTP calls by detailing the same‑origin policy, the conditions that make a request simple, and how browsers automatically issue a CORS preflight OPTIONS request before the actual POST.
This article analyzes the rapidly growing demand for IT positions in Chinese banks, categorizes the banks, details typical roles, written tests, interview formats, and provides concrete salary ranges for each institution, offering a comprehensive view of the banking tech job market.
