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Tech Freedom Circle

Crazy Maker Circle (Tech Freedom Architecture Circle): a community of tech enthusiasts, experts, and high‑performance fans. Many top‑level masters, architects, and hobbyists have achieved tech freedom; another wave of go‑getters are hustling hard toward tech freedom.

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Latest from Tech Freedom Circle

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Tech Freedom Circle

Jan 5, 2026 · Artificial Intelligence

A Three‑Step Guide to Mastering RAG Semantic‑Loss Interview Questions

RAG (Retrieval‑Augmented Generation) is a hot interview topic, and many candidates stumble on semantic‑loss issues; this article dissects a real JD interview case, identifies three core shortcomings, and presents a three‑step technical solution—structure restoration, semantic splitting, and hybrid retrieval—plus a ready‑to‑use answer template.

AI InterviewHybrid SearchRAG

0 likes · 25 min read

A Three‑Step Guide to Mastering RAG Semantic‑Loss Interview Questions

Tech Freedom Circle

Jan 4, 2026 · Backend Development

Choosing Between String, StringBuilder, and StringBuffer for Concatenating 100 Million Strings in a JD Interview

The article dissects a JD interview question about concatenating one hundred million strings, comparing String, StringBuilder, and StringBuffer, and explains how immutability leads to object explosion, how StringBuilder’s default capacity causes costly expansions, and why StringBuffer’s synchronized methods become a performance bottleneck in high‑concurrency scenarios.

GCStringStringBuffer

0 likes · 44 min read

Choosing Between String, StringBuilder, and StringBuffer for Concatenating 100 Million Strings in a JD Interview

Tech Freedom Circle

Jan 3, 2026 · Databases

How Many Values Can MySQL IN Handle? 100K‑10M IDs and the Ultimate Solution

An interview scenario reveals that using a massive IN list (hundreds of thousands of IDs) in MySQL quickly exceeds packet limits, forces full‑table scans, and overloads CPU, while batch IN queries cause network storms; the article dissects these pitfalls and presents three progressive strategies—splitting IN, temporary tables with JOIN, and sharding with stream‑merge—to safely query massive ID sets.

IN ClauseMySQLquery optimization

0 likes · 32 min read

How Many Values Can MySQL IN Handle? 100K‑10M IDs and the Ultimate Solution

Tech Freedom Circle

Dec 31, 2025 · Information Security

Unified SSO via Gateway: Multi‑App Auth & Authz and JWT vs Auth vs Authz

This article walks through a complete design and implementation of a unified single sign‑on system using OAuth2.0 authorization‑code flow, Spring Cloud Gateway, JWT, Redis, and Nacos, comparing JWT, authentication, and authorization while presenting performance metrics, security considerations, and interview‑ready answers.

AuthenticationAuthorizationJWT

0 likes · 59 min read

Unified SSO via Gateway: Multi‑App Auth & Authz and JWT vs Auth vs Authz

Tech Freedom Circle

Dec 30, 2025 · Backend Development

How Java Virtual Threads Supercharge Spring Boot: 3× QPS Boost and 67% Memory Savings

This article explains how Java's new virtual threads (Project Loom) can transform Spring Boot applications, delivering up to three‑fold QPS improvements and up to 67% lower memory usage, by replacing heavyweight platform threads with lightweight coroutine‑style execution, and provides detailed comparisons, benchmarks, code samples, and migration guidance.

JavaProject LoomSpring Boot

0 likes · 51 min read

How Java Virtual Threads Supercharge Spring Boot: 3× QPS Boost and 67% Memory Savings

Tech Freedom Circle

Dec 20, 2025 · Backend Development

How SpringBoot Loads Classes: Deep Dive into ClassLoaders and Bean Creation

This article dissects the SpringBoot class‑loading mechanism, explaining how the JVM parent‑delegation model is selectively overridden with custom class loaders like LaunchedURLClassLoader and RestartClassLoader, and how these changes integrate with Spring's bean lifecycle, auto‑configuration, and practical troubleshooting techniques.

ClassLoaderDependency InjectionDevTools

0 likes · 37 min read

How SpringBoot Loads Classes: Deep Dive into ClassLoaders and Bean Creation

Tech Freedom Circle

Dec 18, 2025 · Interview Experience

How to Calculate P99 (99th Percentile) and Choose the Right Latency Line for Interviews

This article explains why the 99th percentile (P99) is a critical performance metric, how to compute it efficiently with histogram, HDR Histogram and T‑Digest techniques, compares P90 vs P99, and shows how to answer interview questions about latency monitoring and related metrics.

HDR HistogramP99latency

0 likes · 33 min read

How to Calculate P99 (99th Percentile) and Choose the Right Latency Line for Interviews

Tech Freedom Circle

Dec 17, 2025 · Backend Development

Thread Pool: Shared vs Exclusive – How to Choose the Right Strategy for Critical Java Services

This article dissects the interview question “Should thread pools be shared or exclusive?” by exposing common pitfalls, presenting a systematic analysis of isolation versus reuse, and illustrating best‑practice designs with concrete RocketMQ examples, code snippets, and decision‑making guidelines.

Java ConcurrencyRocketMQisolation

0 likes · 22 min read

Thread Pool: Shared vs Exclusive – How to Choose the Right Strategy for Critical Java Services

Tech Freedom Circle

Dec 14, 2025 · Interview Experience

Interview Is Acting: Must‑Know Answers to Ace Every Question

This comprehensive guide turns interview preparation into a performance, offering a step‑by‑step "now‑past‑future" script for self‑introductions, STAR‑based storytelling for challenging projects, concrete Java OOM troubleshooting examples, and proven tactics for answering why you left, strengths, pressure handling, and salary expectations.

CareerOOMSTAR

0 likes · 28 min read

Interview Is Acting: Must‑Know Answers to Ace Every Question

Tech Freedom Circle

Dec 13, 2025 · Backend Development

What’s Wrong with Delayed Double Delete? How Top Tech Companies Elegantly Avoid It

The article explains the delayed double‑delete cache‑invalidation pattern, its four major drawbacks in high‑concurrency environments, and presents four production‑grade alternatives—event‑driven binlog updates, distributed‑lock with versioning, write‑through proxy layers, and logical‑delete with async cleanup—used by leading Chinese internet firms to achieve reliable data consistency.

CachingRedisVersioning

0 likes · 21 min read

What’s Wrong with Delayed Double Delete? How Top Tech Companies Elegantly Avoid It