In this blog post, we’ll explore a common challenge faced by Java developers - testing complex logic within task runners. We’ll discuss a practical approach to isolate and test the logic within task runners effectively.

In modern software development, the process extends beyond simply completing a task and moving on. It entails continuous work on new updates, features, and bug fixes. Therefore, the role of feature flags becomes crucial in the software’s lifecycle. Feature flags can be classified as either static or dynamic, depending on the speed at which their changes are applied to the application’s behavior. In this post, we will not discuss the various types of feature flags; instead, we will concentrate on the different approaches for writing code that depends on these variables and styles.

Singleton is one of the most popular Design Pattern, that we can meet practically in any project. Sometime we try not to use it and design the project Singleton free, but sooner or later we all end up using it. Then question raise how to unit test it and all languages have methods. I run into a small task, where had to write a unit test for a singleton in typescript. Most of my searches were not that great, where in some places people suggested to have a reset() function, while others have suggested cheating ways by using ‘any’ casting. Finally got a good suggestion from my colleague to use extend test class from original singleton, and in constructor purposefully call parent’s constructor, where we actually can do proper reset. (credits to Nathan).

This post will be mostly about the quick summary on Event Loops in JavaScript. I think it is crucial thing to understand for JavaScript developers. For the details of please refer to the conference video presented by Erin Zimmer.

This post describes steps needed to setup connection with .Net Core MVC application and database. May be some of the parts of this code can be used by non-MVC based projects as well (can’t guarantee it because haven’t tried myself). This post has been snippeted from the O’reilly course called The Complete Guide to ASP.NET Core MVC (.NET 6).

Even though its not related to my work directly, I was able to get in touch with Hololens-2. I remember back from my work at KETI (Korea Electronics Technology Institute) when I first time played with Hololens (now its referred as Hololens-1). It was amazing feeling when you can see augmented things with such a great quality and precision just in front of your eye. I would like to admit that Hololens-2 is surely advanced version of previous Hololens. Its much lighter, faster, comfortably sits on your head, can fold screen to your top-head when you stop interacting with mixed-reality.

If we have a goal to build a service using lambda we can serve it using API-Gateway which is fully managed service from aws that makes it easy for developers to create, publish, maintain, monitor and secure of API at any scale. We can find many good examples over there for this kind of stack, but in this post I would like to talk about serving lambda via ALB. Which could endup being cheaper or even free (if you use free 12 month tier aws account). I don’t want to dive into the discussion of what is better API-Gateway where you pay per request count or ALB which is payed by running hours. One thing that challenged me was to setup web-app that would be served as an ALB –> Lambda combined stack.

Running expressJS in lambda we can actually build very frugal startup project, which can have verymuch unknown and unpredictable outcome. That feeling when you have built something and invested money for infrastructure but no user show up. In order to prevent that kind of frustrating experience we could actually start the project with lambda. Which could save us some cash.

This short blog can be used as a quick cheat-sheet for understanding how Web-browser processes the pages. In general everything in the page should be divided and considered under three sections: DOM objects, CSS objects and JS objects. While browser runs through the page it builds a tree out of objects which is later given to renderer to actually draw a page for user.

Parquet format is quite popular and well-used among big-data engineers, and most of the case they have setup to read and check the content of parquet files. But sometimes we may need to quickly check the content of parquet. There are many ways and tools to do that, but I would like to talk about the way to do that using S3 Select feature. Most people who has taken any aws course most probably heard about it, but it passes quickly and unnoticably to our ears. It is quite powerful quick tool to know.