Key things you should know about being a freelancer

Hi, my name is Ivan Ursul and I am a freelance engineer since 2015. It’s been a while since I started my career as an independent freelancer. I started it as an engineer in Upwork, in one of their teams, where I was involved first in reporting backend service, then in the time-tracker pipeline, which is served as a backend...

Detecting memory leaks using JVisualVM and Memory Analyzer Tool

Few days ago I had a problem on one of the projects that I am working on, we had a memory leak. During the two days period our services crashed three times, so I decided to investigate it. Everything which I’m going to talk about is not a rocket science, there’s no clever and tricky tips, it’s just a straighforward...

Migrating from Ghost to Jekyll

Jekyll Why Jekyll ? I decided to use Jekyll, because I had a blog on Ghost platform. I was waiting for a new 1.0 release, but then I suddenly realize that I don’t want to use it, because: I have to maintain it on my own I have to pay 10$ every week for 1GB DigitalOcean instance SSL certificates Ghost...

Microservices interaction at scale using Apache Kafka

Intro Why do people do microservices architecture? Let’s start with a review of a classical, old-school, n-tier application, which is often called a monolith: Everyone worked with this types of applications, we were studying them in university, we did lot’s of projects with this architecture and at first glance, it’s a good architecture. We can immediately start doing systems on...

Concurrency structures written using core java

Motivation The reason for writing this article is a lack of my understanding of Java concurrency. That’s why I decided to create a post with some structures, which I wrote by myself. For sure, you may agree or disagree with me, I encourage to post your thoughts in comments so we can discuss them there. List of structures Implemented: Publish-Subscribe...