With no doubt, Retrofit is the most common API client for android. not only this, it inspires many other libraries on the backend side, e.g. feign and my own spwrap library.

Retrofit comes with pluggable architecture when it comes to processing the response, which is called s.

By default…


Spring Data JPA provides a lot of features on top of JPA. Such as Query methods, Query by examples, and a lot more.

It also integrates with JPA Specifications, QueryDSL, Jooq, and other fantastic libraries.

There’s a specific use-case that exists in most applications which is the need to make the user search by multiple criteria for an entity and its related associations. This is where “Spring Data JPA Mongodb Expressions excels.

Spring Data JPA MongoDB Expressions allows you to use MongoDB query syntax to send the…


Photo by Rumman Amin on Unsplash

Vermin is a smart, simple, and powerful command-line tool for Linux, Windows, and macOS.

It’s designed for developers/tester and others working in IT professionals who want a fresh VM environment with a single command. It uses VirtualBox to run the VM.

Vermin is simple to run if you are aware…


Photo by Michael Dziedzic on Unsplash

Vermin is a smart, simple, and powerful command-line tool for Linux, Windows, and macOS. It’s designed for developers/tester and others working in IT who want a fresh VM environment with a single command. It uses VirtualBox to run the VM.

Vermin allows you to build your own images based on…


Photo by Marc-Olivier Paquin on Unsplash

In this post, we will use vermin to install Elastic Logstash.

We will use vermin as it is a simple virtual machine program that uses Virtualbox as the underlying hypervisor.

To follow this tutorial, you will have to install vermin.

First, you need to install Virtualbox, then for Linux and…


Photo by Antonio Grosz on Unsplash

In this post, we will see an example of using Logstash to read input from a file and write to stdout and apply two filter plugins, the Grok and Geoip.

This video will show the steps: (No Audio, just illustration)

Here we will illustrate what we have done in the video above:

We need to have a configuration file, in my…


Actually, I don’t think this is working, as I got some error:

fatal: [node1]: FAILED! => {“msg”: “The task includes an option with an undefined variable. The error was: ‘kubernetes_join_command’ is ….

In a previous post, we see how to install Kubernetes using shell scripts using vermin.

Today, we will…


Photo by Henry Be on Unsplash

I wanted to test running Server-Sent Event behind an http2 server exposed to the browser.

I wrote a simple HTTP service in Golang using HTTP 1.1 and then played with k3s Kubernetes cluster to deploy the service along with an Nginx as a reverse proxy to the Golang HTTP 1.1…


In this post, I will share my own experience on How I prepared and managed to pass the Certified Kubernetes Application Developer. and Will show What it takes to pass the exam from my own point of view.

I got a %94 score, although I thought I won’t make it…


creating a VM using vermin

In this post, we will use vermin to have Ubuntu VM desktop up and running in minutes using Vermin.

  1. Create Ubuntu VM using vermin
  2. Install on the VM
  3. Start the Ubuntu VM after installation

In this post, we will use , however you are free to install any desktop…

Mohammed Hewedy

Software Developer/Architect

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