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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

Apr 12, 2026 · Artificial Intelligence

What Is Harness Agent? A Deep Dive into the New AI Engineering Framework

Harness Agent is an AI engineering framework that combines a large language model with a runtime control system—called the Harness—to provide task planning, sandboxed execution, tool integration, memory management, safety guardrails, and observability, turning raw model capabilities into reliable, production‑grade agents.

AI engineeringDeerFlowFramework

0 likes · 26 min read

What Is Harness Agent? A Deep Dive into the New AI Engineering Framework

Tech Freedom Circle

Mar 25, 2026 · Backend Development

Cracking Alibaba’s 10M Orders Interview: Architecture Seven‑Suite + Heterogeneous Storage Solution

The article dissects Alibaba’s second‑round interview question on handling 10 million daily order queries, exposing why a single sharding answer fails and presenting a comprehensive architecture‑seven‑suite combined with heterogeneous storage (MySQL, HBase, ClickHouse, ES, Redis, MQ) to achieve high concurrency, low latency, and reliable data consistency.

High ConcurrencyInterview Preparationbackend-architecture

0 likes · 40 min read

Cracking Alibaba’s 10M Orders Interview: Architecture Seven‑Suite + Heterogeneous Storage Solution

Tech Freedom Circle

Mar 19, 2026 · Artificial Intelligence

Failed Alibaba Interview: The 4 RAG Modules and 6 Design Principles You Need

The article dissects a failed Alibaba second‑round interview where the candidate answered only “vector‑search‑enhanced” for a RAG design, and then presents a systematic, four‑module RAG architecture together with six design principles, detailed indexing, query understanding, multi‑path recall, and context generation techniques to help candidates demonstrate comprehensive technical depth.

AI ArchitectureDesign PrinciplesMulti‑Path Recall

0 likes · 22 min read

Failed Alibaba Interview: The 4 RAG Modules and 6 Design Principles You Need

Tech Freedom Circle

Mar 17, 2026 · Databases

Why HyperLogLog Misses 100M Daily Active Users and How Bitmap Solves It

The article dissects an Alibaba interview question on counting 100 million daily active users, showing why HyperLogLog’s error and lack of per‑user state make it unsuitable, and presents a detailed Bitmap‑based architecture—including sharding, pre‑computation, and ClickHouse integration—to achieve precise, high‑performance analytics.

ClickHouseDailyActiveUsersHyperLogLog

0 likes · 16 min read

Why HyperLogLog Misses 100M Daily Active Users and How Bitmap Solves It

Tech Freedom Circle

Feb 8, 2026 · Backend Development

JD Interview: Redis Lock Expiration Mid‑Task – How Redisson’s Watchdog Auto‑Renews

The article explains what occurs when a Redis distributed lock expires before a business operation completes, and details how Redisson’s watch‑dog mechanism automatically renews the lock, covering the underlying principles, configuration, code examples, and comparisons with alternative renewal approaches.

BackendConcurrencyJava

0 likes · 34 min read

JD Interview: Redis Lock Expiration Mid‑Task – How Redisson’s Watchdog Auto‑Renews

Tech Freedom Circle

Feb 5, 2026 · Fundamentals

Will the Code in a finally Block Always Execute? The Underlying Mechanics of Java’s finally

This article explains why Java’s finally block normally runs, dives into the compiler’s code‑copying, the bytecode exception table, JVM dispatch, JIT optimizations, and the design trade‑offs that ensure reliable cleanup while highlighting cases where finally may be skipped.

CompilerDesign PatternsException Handling

0 likes · 29 min read

Will the Code in a finally Block Always Execute? The Underlying Mechanics of Java’s finally

Tech Freedom Circle

Feb 2, 2026 · Backend Development

Why Does Redis Crash? Understanding Eviction Strategies, Their Internals, and Monitoring Metrics

The article explains how Redis eviction policies work, why configuring maxmemory and a proper policy is essential to avoid OOM crashes, details each of the eight policies, shows practical configuration and monitoring commands, and dives into the source‑code implementation of LRU/LFU eviction.

CachingLFULRU

0 likes · 30 min read

Why Does Redis Crash? Understanding Eviction Strategies, Their Internals, and Monitoring Metrics

Tech Freedom Circle

Jan 27, 2026 · Interview Experience

Netease Interview: Write a BlockingQueue in 5 Minutes and Explain Design Patterns & Principles

The article breaks down a common Netease interview task—hand‑coding a BlockingQueue in five minutes—by explaining the underlying lock‑and‑condition mechanism, the relevant design patterns and principles, common pitfalls such as spurious wakeups, and provides a concise, 50‑line Java implementation with step‑by‑step commentary.

BlockingQueueDesign PatternsInterview Preparation

0 likes · 20 min read

Netease Interview: Write a BlockingQueue in 5 Minutes and Explain Design Patterns & Principles

Tech Freedom Circle

Jan 26, 2026 · Interview Experience

NetEase Interview: From Default GC to ZGC—How I Got Slammed Three Times

A NetEase interview probes deep JVM garbage‑collection knowledge, exposing misconceptions about default GC, demanding precise G1/ZGC tuning, and challenging candidates with performance‑critical scenarios that reveal hidden latency and memory‑usage pitfalls.

G1eBPFgc

0 likes · 26 min read

NetEase Interview: From Default GC to ZGC—How I Got Slammed Three Times

Tech Freedom Circle

Jan 24, 2026 · Operations

How to Tackle Excess Connections, DDoS/DoS, CORS and XSS Attacks – A Complete Practical Guide

This article walks through a systematic, production‑grade approach to diagnosing and mitigating connection‑overload, DoS/DDoS, XSS and cross‑origin attacks, covering log analysis, Linux kernel tuning, Nginx rate‑limiting, CDN/DDoS‑protection layers, WAF rules, safe rendering practices, and a hardened CORS configuration template.

BackendDDoS mitigationLinux kernel tuning

0 likes · 48 min read

How to Tackle Excess Connections, DDoS/DoS, CORS and XSS Attacks – A Complete Practical Guide