Petri Kainulainen
@petrikainulainen.bsky.social
Spring ninja, summer rock star, autumn hacker, and winter guru. I write code. Titles are irrelevant.
This blog post highlights six success stories from my short AI assisted engineering journey.
AI Assisted Engineering With an AI Chatbot - From Idea to Working Code - Petri Kainulainen
This blog post highlights six situations when AI assisted engineering helped me to get the job done faster.
www.petrikainulainen.net
November 15, 2025 at 3:19 PM
This blog post highlights six success stories from my short AI assisted engineering journey.
19 interesting SW development articles which I read during October 2025: www.petrikainulainen.net/monthly/soft... - HIGHLIGHTS: solving the wrong problem, your data their rules, and why we tend to avoid public conversations.
Software Development Monthly 10 / 2025 - Petri Kainulainen
The software development monthly highlights 19 interesting or useful blog posts which I read during October 2025.
www.petrikainulainen.net
November 11, 2025 at 8:12 AM
19 interesting SW development articles which I read during October 2025: www.petrikainulainen.net/monthly/soft... - HIGHLIGHTS: solving the wrong problem, your data their rules, and why we tend to avoid public conversations.
HIGHLIGHTS: Taming backend complexity: lessons from a decade of TDD, What's new in JUnit 6, and 2FA testing with Playwright and Mailosaur.
Clean Test Automation Monthly 10 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 14 interesting or useful test automation blog posts which I read during October 2025.
www.petrikainulainen.net
November 3, 2025 at 4:20 PM
HIGHLIGHTS: Taming backend complexity: lessons from a decade of TDD, What's new in JUnit 6, and 2FA testing with Playwright and Mailosaur.
19 interesting SW development blog posts which I read in September 2025. HIGHLIGHTS: why I am declining your AI generated MR, keeping secrets out of logs, and are the SOLID principles outdated
Software Development Monthly 9 / 2025 - Petri Kainulainen
The software development monthly highlights 19 interesting or useful blog posts which I read during September 2025.
www.petrikainulainen.net
October 7, 2025 at 9:16 AM
19 interesting SW development blog posts which I read in September 2025. HIGHLIGHTS: why I am declining your AI generated MR, keeping secrets out of logs, and are the SOLID principles outdated
21 interesting test automation articles which I read during September 2025. Highlights: the Tetris principle, how to optimize your Spring Boot integration tests, and how to write your first performance tests with Grafana k6.
Clean Test Automation Monthly 9 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 21 interesting or useful test automation blog posts which I read during September 2025.
www.petrikainulainen.net
September 30, 2025 at 8:58 AM
21 interesting test automation articles which I read during September 2025. Highlights: the Tetris principle, how to optimize your Spring Boot integration tests, and how to write your first performance tests with Grafana k6.
An interesting article which explains why some people cannot pass technical interviews which include a live coding session.
Live coding sucks
Live coding measure stress, not coding skills
hadid.dev
September 9, 2025 at 3:05 PM
An interesting article which explains why some people cannot pass technical interviews which include a live coding session.
You should always take responsibility for the code you commit.
I Know When You're Vibe Coding
I shouldn’t have to care about this. I don’t want to care about how someone’s code gets into the IDE. Whether you wrote it by hand, copied it from a forum…
alexkondov.com
September 9, 2025 at 10:27 AM
You should always take responsibility for the code you commit.
15 interesting SW development blog posts which I read in August 2025. HIGHLIGHTS: I Know When You Are Vibe Coding, AWS deleted my 10-year account and all data without warning, and Live Coding Sucks.
Software Development Monthly 8 / 2025 - Petri Kainulainen
The software development monthly highlights 15 interesting or useful blog posts which I read during august 2025.
www.petrikainulainen.net
September 8, 2025 at 2:39 PM
15 interesting SW development blog posts which I read in August 2025. HIGHLIGHTS: I Know When You Are Vibe Coding, AWS deleted my 10-year account and all data without warning, and Live Coding Sucks.
Why I Fired Google and Gave an AI Chatbot a Shot: www.petrikainulainen.net/software-dev...
September 4, 2025 at 6:01 PM
Why I Fired Google and Gave an AI Chatbot a Shot: www.petrikainulainen.net/software-dev...
HIGHLIGHTS: how to write automated tests for a legacy application that cannot be unit tested, learn to test production-ready Spring Boot applications, and how to write Playwright tests which verify that the expected interactions happen between our UI and REST API.
Clean Test Automation Monthly 8 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 15 interesting or useful test automation blog posts which I read during august 2025.
www.petrikainulainen.net
September 1, 2025 at 3:14 PM
HIGHLIGHTS: how to write automated tests for a legacy application that cannot be unit tested, learn to test production-ready Spring Boot applications, and how to write Playwright tests which verify that the expected interactions happen between our UI and REST API.
HIGHLIGHTS: the rules and roles of AI assisted testing, how to create a useful logging config for Spring Boot tests, and learn to write performance tests with Playwright and Lighthouse.
Clean Test Automation Monthly 7 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 11 interesting or useful test automation blog posts which I read during July 2025.
www.petrikainulainen.net
August 1, 2025 at 10:05 AM
HIGHLIGHTS: the rules and roles of AI assisted testing, how to create a useful logging config for Spring Boot tests, and learn to write performance tests with Playwright and Lighthouse.
Reposted by Petri Kainulainen
New in my toolkit (after resilience4j and Spring Retry): #failsafe
failsafe.dev
Nice api, clear docs, easy and flexible to integrate and use. Well done.
#java #awesomeEcoSystem
failsafe.dev
Nice api, clear docs, easy and flexible to integrate and use. Well done.
#java #awesomeEcoSystem
Fault tolerance and resilience patterns for the JVM
Failsafe website
failsafe.dev
July 1, 2025 at 10:55 AM
New in my toolkit (after resilience4j and Spring Retry): #failsafe
failsafe.dev
Nice api, clear docs, easy and flexible to integrate and use. Well done.
#java #awesomeEcoSystem
failsafe.dev
Nice api, clear docs, easy and flexible to integrate and use. Well done.
#java #awesomeEcoSystem
Interesting article.
React Still Feels Insane And No One Is Talking About It
mbrizic.com
July 1, 2025 at 9:11 AM
Interesting article.
I will grab Elden Ring and Horizon Forbidden West from the Steam's summer sale. The price is decent and I guess these (+ Rocket League) will keep me entertained for the rest of this year.
July 1, 2025 at 6:56 AM
I will grab Elden Ring and Horizon Forbidden West from the Steam's summer sale. The price is decent and I guess these (+ Rocket League) will keep me entertained for the rest of this year.
HIGHLIGHTS: a good test name is a sentence, how to write parameterized test classes with JUnit 5, and supercharge your Playwright tests with the Chrome DevTools Protocol.
Clean Test Automation Monthly 6 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 14 interesting or useful test automation blog posts which I read during June 2025.
www.petrikainulainen.net
June 30, 2025 at 4:49 PM
HIGHLIGHTS: a good test name is a sentence, how to write parameterized test classes with JUnit 5, and supercharge your Playwright tests with the Chrome DevTools Protocol.
I use a somewhat similar approach.
How I write production-ready Spring Boot applications
This blog post will explain how I currently write Spring Boot applications.
I have been writing Java for over 25 years, and most of that involved Spring and its ecosystem.
I will talk about how I arch...
www.wimdeblauwe.com
June 28, 2025 at 7:16 AM
I use a somewhat similar approach.
I have come to the conclusion that I will monetize my blog. Have you done the same? If yes, what membership plugin / service did you use?
June 10, 2025 at 2:51 PM
I have come to the conclusion that I will monetize my blog. Have you done the same? If yes, what membership plugin / service did you use?
This is an excellent post.
June 10, 2025 at 11:46 AM
This is an excellent post.
Reposted by Petri Kainulainen
✨ New blog post: "STF Milestone 4: Parameterized test classes"
JUnit 5.13 introduced parameterized test classes (in addition to methods). They are a powerful testing tool that has long been missing from JUnit Jupiter...
👉 marcphilipp.de/blog/2025/06...
JUnit 5.13 introduced parameterized test classes (in addition to methods). They are a powerful testing tool that has long been missing from JUnit Jupiter...
👉 marcphilipp.de/blog/2025/06...
June 7, 2025 at 11:52 AM
✨ New blog post: "STF Milestone 4: Parameterized test classes"
JUnit 5.13 introduced parameterized test classes (in addition to methods). They are a powerful testing tool that has long been missing from JUnit Jupiter...
👉 marcphilipp.de/blog/2025/06...
JUnit 5.13 introduced parameterized test classes (in addition to methods). They are a powerful testing tool that has long been missing from JUnit Jupiter...
👉 marcphilipp.de/blog/2025/06...
Reposted by Petri Kainulainen
I think people go through various phases of using AI:
1. AI is just a hype
2. AI seems to be helpful
3. Wow, AI is amazing and it's going to take away our jobs
4. OMG, AI made my codebase a mess
5. Okay, so I need to do the thinking and use AI to carry out the tasks.
1. AI is just a hype
2. AI seems to be helpful
3. Wow, AI is amazing and it's going to take away our jobs
4. OMG, AI made my codebase a mess
5. Okay, so I need to do the thinking and use AI to carry out the tasks.
May 31, 2025 at 4:16 PM
I think people go through various phases of using AI:
1. AI is just a hype
2. AI seems to be helpful
3. Wow, AI is amazing and it's going to take away our jobs
4. OMG, AI made my codebase a mess
5. Okay, so I need to do the thinking and use AI to carry out the tasks.
1. AI is just a hype
2. AI seems to be helpful
3. Wow, AI is amazing and it's going to take away our jobs
4. OMG, AI made my codebase a mess
5. Okay, so I need to do the thinking and use AI to carry out the tasks.
I am testing the Jetbrains AI Assistant and I have noticed that I can pass guidelines to AI chat by following these steps: 1) Open the markdown file which contains the guidelines 2) Open AI Chat and allows access to code base 3) Ask the assistant to read guidelines and generate code. Interesting.
May 31, 2025 at 11:30 AM
I am testing the Jetbrains AI Assistant and I have noticed that I can pass guidelines to AI chat by following these steps: 1) Open the markdown file which contains the guidelines 2) Open AI Chat and allows access to code base 3) Ask the assistant to read guidelines and generate code. Interesting.
Highlights: how to generate good tests with AI, 3 ways to run a Docker container with Testcontainers when we are writing integration tests for Spring Boot applications, and vibe testing with Playwright.
Clean Test Automation Monthly 5 / 2025 - Petri Kainulainen
The clean test automation monthly highlights 23 interesting or useful test automation blog posts which I read during May 2025.
www.petrikainulainen.net
May 31, 2025 at 9:53 AM
Highlights: how to generate good tests with AI, 3 ways to run a Docker container with Testcontainers when we are writing integration tests for Spring Boot applications, and vibe testing with Playwright.
If you want to generate Spring controllers with openapi-generator-maven-plugin and you don't want to include Swagger annotations in the generated code, this comment describes the configuration you have to use: github.com/OpenAPITools...
[BUG] [SPRING] annotationLibrary is ignored · Issue #11460 · OpenAPITools/openapi-generator
Hi. I'm using the latest version of the generator (5.3.1) and, according to the spring generator documentation, I should be able to not generate the Swagger annotations by setting annotationLibrary...
github.com
May 26, 2025 at 7:47 PM
If you want to generate Spring controllers with openapi-generator-maven-plugin and you don't want to include Swagger annotations in the generated code, this comment describes the configuration you have to use: github.com/OpenAPITools...
Good point.
Fluent APIs Are More Than Just Chaining · Poutsma Principles
poutsma-principles.com
May 26, 2025 at 5:56 PM
Good point.
Sometimes vibe-coding is relaxing, and sometimes it's not.
May 21, 2025 at 7:25 PM
Sometimes vibe-coding is relaxing, and sometimes it's not.