Former senior programmer at a Fortune Global 500 company, dedicated to sharing Java expertise. Visit Feng's site: Java Knowledge Sharing, www.java1234.com
The article examines why a company might mandate POST for every API, compares GET and POST characteristics, discusses RESTful best‑practice expectations, highlights the hidden costs of over‑standardization, and presents a more nuanced approach to API design for dynamic and static services.
This article explains why raw collections are unsafe, how Java generics enforce compile‑time type safety, reduce casting, improve code readability, and boost performance, and it walks through generic interfaces, collections, custom generic classes, inheritance rules, diamond syntax, and common restrictions with concrete code examples and diagrams.
A production incident where payment requests succeeded but no order rows were inserted was traced to a missing commit in a special code path, causing a polluted connection to be reused by other services; the article details the debugging steps, root‑cause analysis, code fixes, and preventive measures.
This article explains Java's reflection mechanism, covering its main uses such as dynamic class loading, handling unknown types, accessing private members, and framework development, then walks through basic steps, a complete code example, and discusses its advantages and drawbacks.
The article explains why returning a generic Result wrapper from a Java service layer breaks responsibility separation, harms reusability, complicates exception handling and testing, and obscures transaction boundaries, advocating for returning pure domain objects instead.
This tutorial shows how to implement graceful dynamic data source switching in SpringBoot by combining ThreadLocal with AbstractRoutingDataSource, configuring master/slave databases, adding a @DS annotation with AOP support, and enabling runtime addition of new data sources.
This article walks through building a pure‑Java DOCX‑to‑PDF converter in Spring Boot using docx4j, compares it with alternatives, shows Maven dependencies, provides a utility class and controller example, and explains how to resolve Chinese font garbling on both Windows and Linux.
The article demonstrates how to achieve a ten‑fold reduction in API response time by building a three‑level cache pyramid (Caffeine L1, Redis L2, DB L3) in Spring Boot 3, covering dependencies, configuration, core template code, warm‑up, monitoring, load‑test results and common high‑concurrency pitfalls.
RabbitMQ supports transactional messaging to guarantee atomic delivery, using txSelect to start, txCommit to finalize, and txRollback to abort; this article explains the mechanism, outlines its advantages and performance drawbacks, and provides a complete Java example with step‑by‑step code walkthrough.
The article explains that big‑tech firms ask deep, “onion‑layer” questions to gauge a candidate’s potential and thinking ability, while smaller companies focus on detailed, practical queries to confirm immediate competence, and mismatches between these expectations often cause interview silence.
