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Shepherd Advanced Notes

Dedicated to sharing advanced Java technical insights, daily work snippets, and the power of persistent effort.

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Latest from Shepherd Advanced Notes

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Shepherd Advanced Notes

Jul 9, 2025 · Databases

Comprehensive Guide to Fastest Batch Update Techniques in MyBatis

This article systematically compares six MyBatis batch‑update approaches—including simple for‑loop, foreach XML, CASE WHEN, ON DUPLICATE KEY UPDATE, REPLACE INTO, and MyBatis‑Plus—by presenting concrete code, execution‑time measurements on 10 000 rows, and analysis of I/O, SQL parsing, scalability, and database compatibility, ultimately recommending the most performant and maintainable method for different scenarios.

Batch UpdateCASE WHENMyBatis

0 likes · 13 min read

Comprehensive Guide to Fastest Batch Update Techniques in MyBatis

Shepherd Advanced Notes

Jul 2, 2025 · Fundamentals

45 Tips for Writing Clean, Beautiful Code

This article presents 45 practical coding tips—from naming conventions and formatting to exception handling, thread safety, and design patterns—illustrated with Java examples and real‑world scenarios, helping developers produce readable, maintainable, and robust code.

Design Patternsbest practicesclean code

0 likes · 29 min read

45 Tips for Writing Clean, Beautiful Code

Shepherd Advanced Notes

May 28, 2025 · Backend Development

Why Kafka Outperforms RocketMQ: A Deep Dive into Zero‑Copy and Architecture

The article analyzes why Kafka delivers about 50% higher throughput than RocketMQ, examining zero‑copy mechanisms (mmap vs sendfile), the resulting system‑call and data‑copy differences, and how RocketMQ’s richer feature set trades off raw performance for functionality.

KafkaMessage QueuePerformance

0 likes · 9 min read

Why Kafka Outperforms RocketMQ: A Deep Dive into Zero‑Copy and Architecture

Shepherd Advanced Notes

May 15, 2025 · Backend Development

Deep Dive into Spring Boot Parameter Validation: Implementation, Custom Annotations, and Internationalization

This article explains how Spring Boot leverages JSR‑380 for declarative request validation, walks through the internal processing chain from RequestResponseBodyMethodProcessor to Hibernate Validator, and demonstrates building custom annotations for enum checks and conditional field validation while supporting multilingual error messages.

Hibernate ValidatorInternationalizationJSR-380

0 likes · 11 min read

Deep Dive into Spring Boot Parameter Validation: Implementation, Custom Annotations, and Internationalization

Shepherd Advanced Notes

May 8, 2025 · Backend Development

Missing Parameter Validation Can Crash a Spring Boot Service – A Complete Guide

A real‑world incident where an unchecked null request parameter caused a full‑table query, massive memory usage and OOM is examined, then Spring Boot’s validation framework—including manual checks, annotation‑driven constraints, nested and group validation, and global exception handling—is demonstrated step‑by‑step with code samples.

JavaSpring Bootbackend

0 likes · 18 min read

Missing Parameter Validation Can Crash a Spring Boot Service – A Complete Guide

Shepherd Advanced Notes

Apr 28, 2025 · Operations

Avoid Kafka Pitfalls: Deep Production Lessons on Throughput, Reliability, and Scaling

This article shares hands‑on production experience with Kafka, covering how to tune producer throughput, prevent message loss, control duplicate consumption, handle backlog, maintain ordering, understand rebalance, and explains why Kafka delivers such high performance.

ConfigurationKafkaRebalance

0 likes · 15 min read

Avoid Kafka Pitfalls: Deep Production Lessons on Throughput, Reliability, and Scaling

Shepherd Advanced Notes

Feb 20, 2025 · Backend Development

How Spring Boot Handles Cross-Origin Requests

This article explains the fundamentals of CORS, why browsers enforce the same‑origin policy, how Spring Boot detects and processes cross‑origin and preflight requests, and provides a minimal configuration and JavaScript example to resolve CORS issues in a Spring Boot application.

CORSConfigurationCross-Origin

0 likes · 11 min read

How Spring Boot Handles Cross-Origin Requests

Shepherd Advanced Notes

Feb 17, 2025 · Databases

Master MySQL Master‑Slave Replication: Principles and Step‑by‑Step Setup

This article explains the fundamentals of MySQL master‑slave replication, detailing how binlog‑based data syncing works and providing a complete Docker‑based deployment guide—including configuration files, user creation, replication commands, and troubleshooting tips for a one‑master‑two‑slave cluster.

BinlogDockerHigh Availability

0 likes · 10 min read

Master MySQL Master‑Slave Replication: Principles and Step‑by‑Step Setup

Shepherd Advanced Notes

Feb 5, 2025 · Databases

Elegant Techniques for Group‑Then‑Sort and Top‑Record Retrieval in MySQL & Elasticsearch

The article walks through a common database requirement—grouping rows, sorting within each group, and extracting the first (or top N) records—by preparing sample data, comparing MySQL window functions, subqueries, and JOIN solutions, adding index optimizations, and demonstrating equivalent Elasticsearch aggregations, all backed by concrete performance measurements.

ElasticsearchMySQLSQL

0 likes · 11 min read

Elegant Techniques for Group‑Then‑Sort and Top‑Record Retrieval in MySQL & Elasticsearch

Shepherd Advanced Notes

Jan 17, 2025 · Backend Development

Why @Async Triggers Circular Dependency Errors in Spring and How to Resolve Them

This article explains why Spring cannot resolve circular dependencies when a bean method is annotated with @Async, detailing the underlying bean post‑processor mechanisms, the order of proxy creation, and practical solutions such as removing @Async, using @Lazy, or adjusting bean factory settings.

AOPBeanPostProcessorSpring

0 likes · 15 min read

Why @Async Triggers Circular Dependency Errors in Spring and How to Resolve Them