Software Engineer's Blog
Jason Yang

Jason Yang

Hi, I’m Jason — a senior software engineer with 17+ years of experience building enterprise-grade backend systems across telecommunications, healthcare, and cloud environments. I write about real-world engineering: backend, cloud, AI integration, and system design, with code in Java, Python, C/C++, and React.

Recent Posts

Agent Loops in Claude Code: Knowing When to Stop

Agent Loops in Claude Code: Knowing When to Stop

Claude Code /goal: Make Completion a Deterministic Gate

Claude Code /goal: Make Completion a Deterministic Gate

Running Auto Research in Claude Code — A Bash-Driven Experiment Loop

Running Auto Research in Claude Code — A Bash-Driven Experiment Loop

Obsidian Local Image Attachments: Why I Ditched Imgur

Obsidian Local Image Attachments: Why I Ditched Imgur

Three Claude Code Skills for a Subtitle Workflow

Three Claude Code Skills for a Subtitle Workflow

Harness Engineering: Keeping AI From Running Wild

Harness Engineering: Keeping AI From Running Wild

The Four Layers of AI Engineering: From Prompts to Loops

The Four Layers of AI Engineering: From Prompts to Loops

Obsidian Nord: wider content and fonts for Korean notes

Obsidian Nord: wider content and fonts for Korean notes

Ghostty 1.3: Fixed Tab Titles for Claude Code and Codex

Ghostty 1.3: Fixed Tab Titles for Claude Code and Codex

From Port Forwarding to Cloudflare Tunnel: Moving a Ghost Blog on a Synology NAS

From Port Forwarding to Cloudflare Tunnel: Moving a Ghost Blog on a Synology NAS

When Claude Code won't paste images on Linux (Wayland)

When Claude Code won't paste images on Linux (Wayland)

Fixing Bitwarden Extension Login Failures on Self-Hosted Vaultwarden (Synology Docker)

Fixing Bitwarden Extension Login Failures on Self-Hosted Vaultwarden (Synology Docker)

Running the Ralph Loop in Claude Code — 4 Practical Ways

Running the Ralph Loop in Claude Code — 4 Practical Ways

Should AI Output Be Markdown or HTML? Notes on the Claude Code Debate

Should AI Output Be Markdown or HTML? Notes on the Claude Code Debate

From Pessimistic to Optimistic Locking: A Practical Guide to Retries and Backoff

From Pessimistic to Optimistic Locking: A Practical Guide to Retries and Backoff

Using Claude Code in Zed with Terminal Threads

Using Claude Code in Zed with Terminal Threads

Using Ghostty Split Panes on Linux

Using Ghostty Split Panes on Linux

Understanding LSP with the Rectangle and Square Example in Java

Understanding LSP with the Rectangle and Square Example in Java

Applying OCP with the Strategy Pattern in Java

Applying OCP with the Strategy Pattern in Java

DIP vs DI: Understanding the Difference in Java

DIP vs DI: Understanding the Difference in Java

SOLID Principles in Java

SOLID Principles in Java

Dependency Inversion Principle in Java: Depend on Abstractions, Not Concrete Classes

Dependency Inversion Principle in Java: Depend on Abstractions, Not Concrete Classes

Interface Segregation Principle in Java: Many Small Interfaces Over One Large Interface

Interface Segregation Principle in Java: Many Small Interfaces Over One Large Interface

Liskov Substitution Principle in Java: Subclasses Should Replace Parent Classes Safely

Liskov Substitution Principle in Java: Subclasses Should Replace Parent Classes Safely

Open-Closed Principle in Java: Open to Extension, Closed to Modification

Open-Closed Principle in Java: Open to Extension, Closed to Modification

Single Responsibility Principle in Java: One Class, One Reason to Change

Single Responsibility Principle in Java: One Class, One Reason to Change

opusplan, subagents, /advisor: which Claude Code routing knob does what

opusplan, subagents, /advisor: which Claude Code routing knob does what

Running KakaoTalk and WhatsApp on Linux: A Practical Waydroid Guide for Ubuntu/Kubuntu 25.10

Running KakaoTalk and WhatsApp on Linux: A Practical Waydroid Guide for Ubuntu/Kubuntu 25.10

Beyond LIKE: Fuzzy Search in PostgreSQL with pg_trgm

Beyond LIKE: Fuzzy Search in PostgreSQL with pg_trgm

Fixing Kate's Blank Markdown Preview on Kubuntu 25.10

Fixing Kate's Blank Markdown Preview on Kubuntu 25.10

Chrome Has No Sound on Kubuntu (PipeWire Fix)

Chrome Has No Sound on Kubuntu (PipeWire Fix)

Getting Started with tmux — From Installation to Real-World Setup (Ubuntu/Kubuntu)

Getting Started with tmux — From Installation to Real-World Setup (Ubuntu/Kubuntu)

Using Dolphin Instead of Nautilus on Ubuntu 24.04 (Practical Guide + Caveats)

Using Dolphin Instead of Nautilus on Ubuntu 24.04 (Practical Guide + Caveats)

Claude Code /statusline — A Must-Have When You’re Working Across Multiple Projects

Claude Code /statusline — A Must-Have When You’re Working Across Multiple Projects

Supercharging Claude Code with Codex (What Actually Works)

Supercharging Claude Code with Codex (What Actually Works)

76. Minimum Window Substring

76. Minimum Window Substring

3. Longest Substring Without Repeating Characters

3. Longest Substring Without Repeating Characters

125. Valid Palindrome

125. Valid Palindrome

128. Longest Consecutive Sequence

128. Longest Consecutive Sequence

From SecureCRT to Ghostty: Building a Better SSH Workflow

From SecureCRT to Ghostty: Building a Better SSH Workflow

Complete Guide to CORS in GCP

Complete Guide to CORS in GCP

15. 3Sum

15. 3Sum

11. Container With Most Water

11. Container With Most Water

Understanding the Two Pointers Technique

Understanding the Two Pointers Technique

Kafka Testing Strategy — Spring EmbeddedKafka & Python testcontainers

Kafka Testing Strategy — Spring EmbeddedKafka & Python testcontainers

Implementing a Kafka Consumer in FastAPI — aiokafka AIOKafkaConsumer Guide

Implementing a Kafka Consumer in FastAPI — aiokafka AIOKafkaConsumer Guide

Using Kafka in FastAPI — aiokafka Producer Implementation Guide

Using Kafka in FastAPI — aiokafka Producer Implementation Guide

Using Kafka in Spring Boot — Producer & Consumer Implementation Guide

Using Kafka in Spring Boot — Producer & Consumer Implementation Guide

Kafka Setup & Topic Design — A Practical Local Development Guide

Kafka Setup & Topic Design — A Practical Local Development Guide

Kafka Essentials — A Practical Beginner’s Guide

Kafka Essentials — A Practical Beginner’s Guide

HTTPS Setup Guide with Let's Encrypt (Certbot + Nginx + Docker)

HTTPS Setup Guide with Let's Encrypt (Certbot + Nginx + Docker)

Local Docker Registry & Multi-Service Build/Deploy Guide

Local Docker Registry & Multi-Service Build/Deploy Guide

Java Set Explained (HashSet vs LinkedHashSet vs TreeSet)

Java Set Explained (HashSet vs LinkedHashSet vs TreeSet)

Setting Up Caddy Reverse Proxy with Automatic HTTPS (Docker)

Setting Up Caddy Reverse Proxy with Automatic HTTPS (Docker)

How to Log in to the TELUS Network Access Hub (NAH)

How to Log in to the TELUS Network Access Hub (NAH)

What Is MapStruct and Why Do We Need It?

What Is MapStruct and Why Do We Need It?

The Canonical Way to Manage Config with Pydantic v2

The Canonical Way to Manage Config with Pydantic v2

FastAPI (Python) vs Spring Core (Java) Perspective Comparison

FastAPI (Python) vs Spring Core (Java) Perspective Comparison

FastAPI Dependency Injection (DI) Guide

FastAPI Dependency Injection (DI) Guide

Python Singleton Implementation Guide (Pythonic & Practical)

Python Singleton Implementation Guide (Pythonic & Practical)

How to Set Up SSH Key-Based Login from Ubuntu to Synology NAS (DSM 7.1)

How to Set Up SSH Key-Based Login from Ubuntu to Synology NAS (DSM 7.1)

Claude Code Agents Guide: How Skills Power Your Subagents

Claude Code Agents Guide: How Skills Power Your Subagents

Claude Code Skills Guide: How to Automate Your Development Workflow

Claude Code Skills Guide: How to Automate Your Development Workflow

Enforcing Team Architecture with .claude/rules in Claude Code (FastAPI Practical Guide)

Enforcing Team Architecture with .claude/rules in Claude Code (FastAPI Practical Guide)

How to Install NVIDIA Driver on Ubuntu 24.04 (GTX 1660 Ti Laptop): Solving Dependency Conflicts

How to Install NVIDIA Driver on Ubuntu 24.04 (GTX 1660 Ti Laptop): Solving Dependency Conflicts

Streamlining Ghost Blog Feature Images: A Developer’s Guide to Bash & ImageMagick

Streamlining Ghost Blog Feature Images: A Developer’s Guide to Bash & ImageMagick

Generate Speaker-Labeled Subtitles with Whisper and pyannote.audio on Ubuntu 24.04

Generate Speaker-Labeled Subtitles with Whisper and pyannote.audio on Ubuntu 24.04

Understanding Lombok’s @Builder and Default Field Values

Understanding Lombok’s @Builder and Default Field Values

How to Install Docmost on Synology NAS (DS916+) with Docker

How to Install Docmost on Synology NAS (DS916+) with Docker

Use jq to Format JSON in Vim on Ubuntu (Prettify & Minify)

Use jq to Format JSON in Vim on Ubuntu (Prettify & Minify)

How to Set Up Vaultwarden (Bitwarden) on a Synology NAS — The Best Free Alternative to LastPass

How to Set Up Vaultwarden (Bitwarden) on a Synology NAS — The Best Free Alternative to LastPass

Running Claude Code CLI with DeepSeek-Reasoner

Running Claude Code CLI with DeepSeek-Reasoner

Why Claude Appears in Your GitHub Contributors — and How to Fix It

Why Claude Appears in Your GitHub Contributors — and How to Fix It

Extending Claude Code's Memory: Installing and Using claude-mem

Extending Claude Code's Memory: Installing and Using claude-mem

PostgreSQL TIMESTAMP WITH TIME ZONE: A Practical Guide for Global Services

PostgreSQL TIMESTAMP WITH TIME ZONE: A Practical Guide for Global Services

PostgreSQL User Creation and Permission Setup

PostgreSQL User Creation and Permission Setup

Stop Using key.json: How to Configure GCP Service Account Impersonation

Stop Using key.json: How to Configure GCP Service Account Impersonation

Stop Claude Code from Killing Your Ubuntu Session — The Swap Setup I Wish I Had Sooner

Stop Claude Code from Killing Your Ubuntu Session — The Swap Setup I Wish I Had Sooner

ripgrep (rg): The Fastest Way to Search Your Code

ripgrep (rg): The Fastest Way to Search Your Code

Ubuntu Clamshell Mode: Use a Closed Laptop With an External Monitor

Ubuntu Clamshell Mode: Use a Closed Laptop With an External Monitor

How to Install and Configure OpenSSH Server on Ubuntu

How to Install and Configure OpenSSH Server on Ubuntu

How to Find and Kill Processes Occupying a Port (lsof, netstat, ss)

How to Find and Kill Processes Occupying a Port (lsof, netstat, ss)

Understanding TCP: Architecture, Segment Structure, and Handshakes

Understanding TCP: Architecture, Segment Structure, and Handshakes

How to Disable Wi-Fi Power Saving on Ubuntu to Prevent SSH Lag

How to Disable Wi-Fi Power Saving on Ubuntu to Prevent SSH Lag

How to Set a Static WiFi IP on Ubuntu (Without Router Access)

How to Set a Static WiFi IP on Ubuntu (Without Router Access)

33. Search in Rotated Sorted Array

33. Search in Rotated Sorted Array

How to Open a Specific Port on Ubuntu with UFW

How to Open a Specific Port on Ubuntu with UFW

How to Back Up and Restore SecureCRT Settings on Ubuntu

How to Back Up and Restore SecureCRT Settings on Ubuntu

Divide and Conquer (D&C): Beyond Merge Sort

Divide and Conquer (D&C): Beyond Merge Sort

[Synology] How to Enable SSH and Log in as Root

[Synology] How to Enable SSH and Log in as Root

[SecureCRT] How to Set Up a Serial Console Connection

[SecureCRT] How to Set Up a Serial Console Connection

Why is Binary Search O(log n)?

Why is Binary Search O(log n)?

153. Find Minimum in Rotated Sorted Array

153. Find Minimum in Rotated Sorted Array

Adding a gRPC Endpoint to order-service: A Practical Guide

Adding a gRPC Endpoint to order-service: A Practical Guide

Dynamic Programming Explained: The Missing Link with Divide & Conquer

Dynamic Programming Explained: The Missing Link with Divide & Conquer

152. Maximum Product Subarray

152. Maximum Product Subarray

Download High-Quality MP3s from YouTube on Ubuntu with yt-dlp

Download High-Quality MP3s from YouTube on Ubuntu with yt-dlp

Batch Trim MP3 Files on Ubuntu using FFmpeg

Batch Trim MP3 Files on Ubuntu using FFmpeg

How to Merge Two Mono Audio Files into Stereo with FFmpeg on Ubuntu

How to Merge Two Mono Audio Files into Stereo with FFmpeg on Ubuntu

Batch Convert Video to MP3 on Ubuntu with FFmpeg

Batch Convert Video to MP3 on Ubuntu with FFmpeg

How to Convert WAV (MP4) to MP3 Using FFmpeg

How to Convert WAV (MP4) to MP3 Using FFmpeg

Troubleshooting SecureCRT "Key Exchange Failed" with Ubuntu 22.04 (OpenSSH)

Troubleshooting SecureCRT "Key Exchange Failed" with Ubuntu 22.04 (OpenSSH)

Pydantic vs dataclass - When to Use Which?

Pydantic vs dataclass - When to Use Which?

The OSI 7 Layers Model: Protocols, PDUs, and Devices

The OSI 7 Layers Model: Protocols, PDUs, and Devices

How to Resolve ACPI Errors When Installing Ubuntu 22.04 on ASUS GA502GU-PB73

How to Resolve ACPI Errors When Installing Ubuntu 22.04 on ASUS GA502GU-PB73

53. Maximum Subarray

53. Maximum Subarray

Modern Java Exception Handling: Best Practices and Logging Strategies

Modern Java Exception Handling: Best Practices and Logging Strategies

Designing Effective Custom Exceptions in Java

Designing Effective Custom Exceptions in Java

How Real-World Java Developers Handle Exceptions: Rethinking Checked vs. Unchecked

How Real-World Java Developers Handle Exceptions: Rethinking Checked vs. Unchecked

238. Product of Array Except Self

238. Product of Array Except Self

Understanding Prefix and Suffix Patterns

Understanding Prefix and Suffix Patterns

217. Contains Duplicate

217. Contains Duplicate

Understanding Java Exception Hierarchy

Understanding Java Exception Hierarchy

Understanding One-Pass Algorithms and Greedy Strategies

Understanding One-Pass Algorithms and Greedy Strategies

121. Best Time to Buy and Sell Stock

121. Best Time to Buy and Sell Stock

Vim Setup with vim-plug on Ubuntu

Vim Setup with vim-plug on Ubuntu

How to Install SecureCRT on Ubuntu 24.04

How to Install SecureCRT on Ubuntu 24.04

A Guide to Automating Connections with SecureCRT Logon Scripts

A Guide to Automating Connections with SecureCRT Logon Scripts

GCP Artifact Registry & Poetry Integration Guide

GCP Artifact Registry & Poetry Integration Guide

Using Mathematical Formulas in Ghost: Adding LaTeX Support with KaTeX

Using Mathematical Formulas in Ghost: Adding LaTeX Support with KaTeX

Turn an Ubuntu Laptop Into an Always-On Headless Server (Lid Closed)

Turn an Ubuntu Laptop Into an Always-On Headless Server (Lid Closed)

Spring Boot: Fixing "Parameter 0 of constructor required a bean of type String"

Spring Boot: Fixing "Parameter 0 of constructor required a bean of type String"

How to Update ASUS BIOS Without a Battery (The F11 Trick)

How to Update ASUS BIOS Without a Battery (The F11 Trick)

Rate Limiting vs. Throttling: What’s the Difference?

Rate Limiting vs. Throttling: What’s the Difference?

How to change Hostname on Amazon Linux Permanently

How to change Hostname on Amazon Linux Permanently

A Comprehensive Guide to Spring Boot & Swagger (OpenAPI) Integration

A Comprehensive Guide to Spring Boot & Swagger (OpenAPI) Integration

Securely Connect to GCP Cloud SQL from Your Local Network Using Cloud SQL Auth Proxy

Securely Connect to GCP Cloud SQL from Your Local Network Using Cloud SQL Auth Proxy

Reliability vs. Availability

Reliability vs. Availability

Managing FastAPI Projects with Poetry, A Step-by-Step Guide

Managing FastAPI Projects with Poetry, A Step-by-Step Guide

Pydantic v1 → v2 Migration Guide for FastAPI Projects

Pydantic v1 → v2 Migration Guide for FastAPI Projects

Checked vs Unchecked Exceptions in Java

Checked vs Unchecked Exceptions in Java

Setting Up a Modern Vim 9.x IDE on Ubuntu or Linux

Setting Up a Modern Vim 9.x IDE on Ubuntu or Linux

How to Set an SSH Login Banner on Ubuntu 24.04

How to Set an SSH Login Banner on Ubuntu 24.04

How to get rid of ^M from a text file on Linux of Unix

How to get rid of ^M from a text file on Linux of Unix

Changing the Default Terminal to Terminator on Ubuntu

Changing the Default Terminal to Terminator on Ubuntu

set guifont Syntax for gVim on Windows vs. Ubuntu

set guifont Syntax for gVim on Windows vs. Ubuntu

WireGuard Client Setup and Disconnection on Ubuntu

WireGuard Client Setup and Disconnection on Ubuntu

Batch Rename Files Using 'rename' and Regex

Batch Rename Files Using 'rename' and Regex

1. Two Sum

1. Two Sum

Stop Fighting Your IME in Vim - Auto-Switch with `vim-im-select`

Stop Fighting Your IME in Vim - Auto-Switch with `vim-im-select`

Fix Bluetooth Audio Stutter in Chrome on Ubuntu 24 (The A2DP Lock)

Fix Bluetooth Audio Stutter in Chrome on Ubuntu 24 (The A2DP Lock)

Mastering React Query (TanStack Query) - A Complete Guide to useQuery and useMutation

Mastering React Query (TanStack Query) - A Complete Guide to useQuery and useMutation