Design is Code - Deterministic AI Code Generation with UML and London-Style TDD
AI writes code fast. You review it slow. That’s not collaboration — that’s exploitation.
Posts by Year
2026
Thinking on SDD AI Development
Vibe coding is for spikes. Spec-driven development is for production. Before you let an LLM generate code, you should know how every element works.
2025
Deploying an AI Agent to AWS: OpenAI Agents SDK + FastAPI + Lambda
Deploy a production-ready AI agent to AWS Lambda using OpenAI Agents SDK, FastAPI, and Terraform.
The Control Spectrum: 8 AI Orchestration Patterns from Full Control to Full Autonomy
AI architecture isn’t binary. It’s a spectrum.
Choosing the Right LLM for Generative vs Discriminative Tasks
Choosing the wrong model for the wrong task leads to unstable systems, wasted compute, and unpredictable behavior.
Should You Migrate to Open Source Model?
What if GPT-4o-mini updates and breaks your prompts? Or gets retired?
Intent Recognition Case Study: Why Conceptual Prompts Won
from 5/10 to 10,000/10,000.
The Fastest Way to Deploy Your AI Agent to AWS Lambda
You’ve built an AI agent. You need it to get to the cloud in 10 minutes.
Programmatic vs Conceptual Prompts
Programmatic prompts: 87% accuracy on complex tasks, 68% on simple ones. Conceptual: the reverse. Know the difference.
Prompts for Weaker LLM Models
Move complexity from prompts to code. Weaker models excel when you simplify their job.
Scalable Prompt Design
Separate stable concepts from changing details. Your prompts become maintainable, not messy.
Evaluating LLM Models
Skip evaluation, risk failure. AI without testing is hope, not strategy.
Prompt Engineering 101
The art and science of building LLM-based applications.
AI Hallucinations Explained
AI creates compelling stories but fabricates facts. Learn to spot and stop hallucinations.
AI Workflows vs AI Agents
Autonomy is the dividing line. Workflows execute predefined steps. Agents decide their own path.
2024
Prototyping AI with Gradio
Build AI interfaces fast. Gradio turns Python functions into shareable web apps.
2022
From If-Else to DSL: How Software Evolves Toward Configuration-Driven Systems
From hardcoded logic to configuration-driven architectures, with complete Java examples.
Improve LLM Answer Quality
Better prompts, better context, or better training. Three levers for quality answers.
Composite Pattern for Recursion
A practice of using composite to resolve a recursive issue.
Set up a composite bean
A bean represents part-whole hierarchies.
Use multi git accounts on mac
One for company, one for yourself.
2021
Add CloudWatch Alarms to A Lambda Function
Better monitoring your app.
Debug a SQL performance issue (aka, how to read a query plan)
aka, how to read a query plan
Use AWS X-Ray in Lambda
Identify performance bottlenecks
Convert unit between metric and imperial in Java
Unit convertion, e.g., Metric to imperial
AWS Lambda with Java
some lambda related concepts
AWS CDK 101
Version control your infrastructure is not a dream
Pure React Study Notes
Learn some React basics.
Quarkus API First Development
With Swagger Open API
2020
AWS CloudFormation 101
Simplify infrastructure management
E2E Testing with Cypress
// todo
Doing LeetCode
with java and python
On Data Structures
References
On Big O Notation
Big O notation is a mathematical concept used in computer science to describe the time complexity and space complexity of algorithms.
Common System Design Questions
Some common system design questions
Servlet Container and Spring Framework
Servlet Container vs. Spring Containers (not finished yet)
Validations in Spring
Spring integrates Bean Validation and gives you more
Spring Scheduled Tasks Stop Working
Investigate and fix stopped @Scheduled methods in Spring.
AWS SDK for Java 101
Build Java application with AWS services
Pass AWS SAA Certification, SAA-C01
AWS Certified Solutions Architect - Associate, SAA-C01
AWS Services Study Notes, Integration
SNS, SQS, etc.
AWS Servcies - Monitoring
CloudWatch, cloutTrail, etc.
AWS Servcies - Security
Cognito, IAM, KMS, IDF, etc.
AWS Servcies - Databases
RDS, Aurora, DynamoDB, ElastiCache, DMS, EMR, Kinesis, etc.
AWS Servcies - Networking &CDN
VPC, CloudFront, Route 53, ALB, etc.
2019
AWS Servcies - Storage
S3, Glacier, EBS, Stoarage Gateway, SnowX, etc.
AWS Servcies - Compute
EC2, Auto Scaling, ELB, Serverless, EB, ECS, CloutFormation, etc.
AWS Key Concepts
AWS SAA: Key Concepts
Document APIs using Swagger
Use Swagger to document Spring boots porject’s APIs
Parsing JSON using jq
Parse JSON using jq in the bash command line.
Upgrade A Spring Boot Project from 2.0 to 2.1
Upgrade Java, Spring Boot, Gradle, Flyway, etc.
How to Insert a Column in PostgreSQL
Insert (not add) a column in PostgreSQL is quite a mission.
Got Spring Professional Certificated at Aug 2019
Got Spring Professional Certificated at Aug 2019
Java Enum and How to Persist It
Should use Enums any time you need to represent a fixed set of constants
Spring Boot Security 5 Basic
Powerful and highly customizable authentication and access-control.
Unit Test Terms
Terms using in Unit Tests.
Java Bean VS Spring Bean
A Java object can be a JavaBean, a POJO and a Spring bean all at the same time.
Session is Lost in Session Scope Controller in Spring MVC App
Why is my session lost and created as new in every servlet request?
NPM Semantic Versioning
We should tag projects like NPM does.
Spring Security in Spring Certification
Spring Security in Pivotal Spring Professional Certification (6%).
Spring OAuth2 Notes
Spring OAuth2 101
Spring RestTemplate
Spring RestTemplate 101.
Java Long Value Cacheing
The cache size may be controlled by -XX:AutoBoxCacheMax=<size> option.
Delete and Create Records Violates Constraints in Spring Data Jpa
Still haven’t found a decent answer in StackOverFlow.
IDEA IntelliJ Config for Java Projects
IDEA IntelliJ Config for Java
Spring Testing in Spring Certification
Spring test in Pivotal Spring professional certification (4%).
Mockito Basic
“Once,” said the Mock Turtle at last, with a deep sigh, “I was a real Turtle.” —Alice In Wonderland, Lewis Carroll
2018
Spring REST in Spring Certification
Spring REST in Pivotal Spring professional certification (6%).
Spring MVC in Spring Professional Certification
Spring MVC in Pivotal Spring professional certification(8%).
Spring Data Management in Spring Certification
Spring Data Management in Spring Professional Certification (16%).
Spring AOP in Spring Certification
Spring AOP in Spring Certification(8%).
Converting Date Time in Java
Converting Date Time in Java
Spring Boot in Spring Professional Certification
Spring Boot in Pivotal Spring professional certification (32%).
Spring Core in Spring Certification
Spring Core in Spring Certification (20%).
Integrate Spring Boot and Angular
Setup a project with Spring Boot and Angular.
Opinionated Final Variables in Java
I use final whenever it is appropriate.
Returning JSON in Spring Boot
Converting Json in Spring projects.
Searching Text Using grep in Linux
How to search text in your files in Linux?
Flex Box Basic
Get out of nightmare that positioning elements with CSS.
Return Early and Give up Single Exit Point
return early and give up single exit point
Using Pipes Within ngModel on Input Elements in Angular
Got an error: Cannot have a pipe in an action expression.
JSON Manipulation with Javascript
{“quote”:”You miss 100% of the shots you don’t take.”,”author”:”Wayne Gretzky”}
Learn Test-Driven Development (TDD) from Uncle Bob
The jury is in. The controversy is over. The debate has ended. The conclusion is: TDD works.
Build A 360 Photo View Page
Handle and view a 360 photo.
Lombok in Spring
Lombok makes Java prettier, and your life easier.
Spring Data JPA Basic
Additional capabilities beyond core spring and JPA.
Concatenating Java Strings
Behavior of String literals is very confusing.
Filenames That Cross Platforms
The most conservative file naming conventions provide the most cross-platform compatibility.
Why Some Code Needed To Be Synchronized
I found one of my old notes… But still need to do more investigation. // todo
Setup a simplest Spring Project Demo Project
A Spring Demo project. See: https://github.com/digitalsonic/geektime-spring-family
Jest, Javascript unit testing
Unit Testing in JavaScript
2017
Beginning AWS, Why and How
AWS does everything. This the first step.
How to Submit a Form
Submits user’s data and sends data to a server.
How to Pass OCAJP Swiftly
I have no idea. It takes efforts.
Prepare for OCAJP, (6)
Exceptions.
Prepare for OCAJP, (5)
Design classes.
Prepare for OCAJP, (4)
Methods and Encapsulation.
Prepare for OCAJP, (3)
String and some common APIs.
Prepare for OCAJP, (2)
Java Operators and Statements.
Prepare for OCAJP, (1)
Java Building Blocks.
HashMap 101
HashMap is fast.
Using Java Optional
Less NPE
JDBC 101-ish
JDBC is an API for connecting and executing queries on a database. Relatively low-level, it’s the foundation of most ORMs and other high-level data access l...
Create Couch Views in Spring
CouchDB is one of NoSQL database, uses JSON to store data, Javascript as its query language using MapReduce, and Http for an API.
Linux System Load Average Explained
Load Avg: 2.56, 2.26, 2.14
Java Constructors 101
The method that constructs your object.
Linux Basic Commands for Files and Directories
Essential commands to manipulate files and directories on Linux.
Use cURL to Transfer Data
cURL is a command line tool for getting or sending files using URL syntax.
Everyday PSQL Commands
PostgreSQL Cheat Sheet.
Vim Editor 101
How to quit vim? - -!
How to Debug PHP Code
There must be a better way. But this is the one I’m currently using.
Set up and Run Junit in a Java project
Set up and Run Junit in a Java project.
Types of Software Testing
Test makes perfect.
What I Did After Updating Database by Mistake?
So sorry that I falsely updated the database with the following script:
2016
Migrate SSRS Reports to Another Server
Watch my Youtube video to get details!
Thinking in jQuery
jQuery, live long and prosper!
SQL Server Configuration
These are my notes while using SQL Server 2016.
2015
Understanding SQL Server Connection Strings
SQL Server Connection Strings.
CSS Selectors
Select the element(s)
How to Find Free Programming Resources
Free Programming Resources.
How to Create a Simple Flowchart
A simple flowchart representing a process for dealing with a non-functioning lamp.
Git Commands
Git Commands
How to Test Jekyll Website Locally
Preview your site and help troubleshoot failed Jekyll builds.