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Latest from CodeNotes

50 recent articles

CodeNotes

Jul 16, 2026 · Backend Development

Proper Enum Handling Across Query Params, Request Body, and Database in Spring Boot

The article demonstrates how Spring Boot can automatically convert strings to enums for query and path parameters, introduces a unified StringToEnumConverterFactory, configures Jackson for case‑insensitive enum deserialization in @RequestBody, and uses a JPA AttributeConverter to persist enums, removing repetitive manual conversion code.

ConverterFactoryEnumJackson

0 likes · 8 min read

Proper Enum Handling Across Query Params, Request Body, and Database in Spring Boot

CodeNotes

Jul 14, 2026 · Backend Development

4 Common @RequestBody Pitfalls That Can Crash Your Spring Apps

The article explains how @RequestBody binds JSON via HttpMessageConverter using Jackson, then details four frequent issues—empty bodies, extra or unknown fields, date‑format mismatches, and deep nesting causing circular serialization—and provides concrete code‑level solutions such as validation, global exception handling, Jackson configuration, and DTO usage.

DTOJacksonJavaTimeModule

0 likes · 10 min read

4 Common @RequestBody Pitfalls That Can Crash Your Spring Apps

CodeNotes

Jul 12, 2026 · Backend Development

What’s the Real Difference Between @Configuration‑Based @Bean and @Component in Spring?

The article demonstrates that @Configuration classes are CGLIB‑proxied, ensuring @Bean methods are intercepted so internal calls respect container singleton semantics, whereas @Component classes lack this proxy, causing each @Bean call to create a new instance, and explains when to use each approach.

BeanConfigurationSpring

0 likes · 10 min read

What’s the Real Difference Between @Configuration‑Based @Bean and @Component in Spring?

CodeNotes

Jul 8, 2026 · Backend Development

Filter, Interceptor or AOP in Spring Boot – How to Choose the Right One

Spring Boot offers three mechanisms—Filter, Interceptor, and AOP—to intercept requests, each with distinct execution order, capabilities, and suitable scenarios; this article explains their differences, shows code examples, provides a comparison table, decision tree, and real‑world use cases to guide proper selection.

AOPInterceptorRequest Handling

0 likes · 12 min read

Filter, Interceptor or AOP in Spring Boot – How to Choose the Right One

CodeNotes

Jun 10, 2026 · Backend Development

After a Decade with Map, Are You Still Using containsKey + get + put?

The article reviews the seven Java 8 Map convenience APIs—getOrDefault, putIfAbsent, computeIfAbsent, computeIfPresent, compute, merge, and forEach—plus replaceAll and Map.of, showing concise code examples, best‑practice recommendations, concurrency considerations, and common pitfalls for modern Java developers.

APICollectionsConcurrency

0 likes · 10 min read

After a Decade with Map, Are You Still Using containsKey + get + put?

CodeNotes

Jun 10, 2026 · Fundamentals

How Java 8’s Default and Static Interface Methods Transform Design Patterns

The article explains how Java 8 added default and static methods to interfaces—allowing method bodies, enabling backward‑compatible extensions, illustrating usage with code examples, handling multiple‑interface conflicts, and introducing Java 9 private methods, while summarizing common pitfalls and best‑practice guidelines.

InterfaceJavaJava 8

0 likes · 9 min read

How Java 8’s Default and Static Interface Methods Transform Design Patterns

CodeNotes

Jun 10, 2026 · Frontend Development

16 Practical CSS Tricks Using :has() to Replace JavaScript

The new CSS :has() selector finally lets parents be selected based on child states, eliminating dozens of lines of JavaScript; this article demonstrates sixteen real‑world use cases, explains compatibility across major browsers, and offers performance tips for safe adoption.

:has()CSSCSS tricks

0 likes · 9 min read

16 Practical CSS Tricks Using :has() to Replace JavaScript

CodeNotes

Jun 8, 2026 · Backend Development

Why Overriding equals Requires Overriding hashCode: An Interview‑Ready Guide

The article explains the contract between equals and hashCode in Java, shows what goes wrong when only one is overridden, demonstrates the correct implementation with Objects.equals and Objects.hash, covers IDE/Lombok generation, JPA entity nuances, inheritance pitfalls, records, and common anti‑patterns.

HashMapJavaLombok

0 likes · 9 min read

Why Overriding equals Requires Overriding hashCode: An Interview‑Ready Guide

CodeNotes

Jun 7, 2026 · Industry Insights

2026 Gaokao: Is Majoring in Computer Science or Software Engineering a Trap or the Right Path in the AI Era?

In the AI era, the article analyzes how AI reshapes computer science and software engineering majors, showing that low‑end coding jobs are being replaced while high‑end architecture and AI‑focused roles surge, and provides a tiered major ranking, score‑based recommendations, university selection criteria, and four‑year study pitfalls to guide 2026 Gaokao applicants.

Artificial IntelligenceComputer ScienceJob Market

0 likes · 10 min read

2026 Gaokao: Is Majoring in Computer Science or Software Engineering a Trap or the Right Path in the AI Era?

CodeNotes

Jun 7, 2026 · Frontend Development

Which React Global State Library Wins? Redux, Zustand, MobX, or Context (3‑Minute Guide)

This article compares Redux Toolkit, Zustand, MobX, and React Context for global state management, offering a decision matrix, concrete code examples, practical tips, and scenario‑based recommendations so developers can choose the most suitable solution for their project's size, complexity, and team dynamics.

Context APIMobXReAct

0 likes · 12 min read

Which React Global State Library Wins? Redux, Zustand, MobX, or Context (3‑Minute Guide)