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The article walks through building a secure QR‑code login flow with Spring Boot, explaining why the QR should contain only a short‑lived random identifier, how to model four login states in Redis, avoid embedding JWTs, use WebSocket for instant updates, and enforce strict one‑time exchange checks.
The article explains why the standard MultipartFile upload fails for multi‑gigabyte files, then details a Spring Boot solution that splits files into 10 MB chunks, uses SHA‑256 hashes for identification, supports resumable and instant uploads, and safely merges chunks on the server.
This article explains how Spring Security 7.1 natively supports Passkey/WebAuthn, walks through the registration and authentication flows, shows the minimal Java configuration and JDBC persistence, and discusses migration strategies and security advantages over traditional password logins.
The article explains how JDK Flight Recorder (JFR) provides low‑overhead, continuous JVM event recording that outperforms traditional snapshot tools like top, jstack, and jmap, and offers practical commands and use‑cases for diagnosing CPU spikes, GC issues, thread contention, and latency problems in production Java services.
The article analyzes why MySQL and Redis cannot guarantee strong consistency with simple cache‑aside patterns, explains the pitfalls of delayed double delete, and presents a tiered Java design—including transaction‑after‑commit deletion, retryable invalidation, CDC/Outbox pipelines, TTL safeguards, and multi‑level cache considerations—to achieve reliable cache consistency.
A Java thread pool that looks larger can actually cause out‑of‑memory errors when core parameters such as core size, max size, queue type, keep‑alive time, thread factory, and rejection policy are mis‑configured, leading to uncontrolled task accumulation and resource exhaustion in production.
When a Java application that uses Spring’s @Scheduled moves from a single server to a cluster, the same job may execute on every node, causing duplicate orders, messages, and data; the article explains why this happens, examines common lock‑based fixes and their pitfalls, and proposes a robust, idempotent, sharded task architecture.
The article explains why deep pagination with large offsets becomes increasingly slow, why adding indexes often does not help, examines common “optimizations” like delayed joins, introduces cursor (keyset) pagination as a high‑performance alternative, and provides practical guidelines for designing pagination APIs in Java back‑ends at scale.
A recent Stack Overflow discussion argues that AI coding agents will turn every developer into a full‑stack builder, allowing Java programmers to deliver complete products without mastering React, while emphasizing the continued need for deep domain expertise.
Microsoft’s study of tens of thousands of engineers shows AI coding agents raise merged pull requests by 24%, but the metric masks deeper issues: faster code production creates verification bottlenecks, knowledge debt, and a shift from coding to review that Java teams must address.
