George Antonopoulos

Full Stack Software Engineer

AWS Certified Developer Exam Notes

Recently I passed the AWS Certified Developer Associate exam. During my preparation for this exam, I collected some exam notes from different sources (courses, tutorials, and AWS docs). Those notes cover all the different fields from which the exam questions are derived. The post is not intended to act as the single studying resource of your preparation. The main intention of Read more about AWS Certified Developer Exam Notes[…]

AWS Certified Solutions Architect Exam Notes

Recently I passed the AWS Certified Solution Architect Associate exam. During my preparation for this exam, I collected some exam notes from different sources (courses, tutorials, and AWS docs). Those notes cover all the different fields from which the exam questions are derived. The post is not intended to act as the single studying resource of your preparation. The main intention of Read more about AWS Certified Solutions Architect Exam Notes[…]

Migrate a Spring Boot app to NodeJS

Two of the most powerful technologies today for building Restful API applications are the Spring Boot and the NodeJS frameworks. Recently, I was working on an application that was divided into two parts. A backend API server built with Spring Boot and a frontend cross-platform mobile application. The frontend was communicating through HTTP with the Read more about Migrate a Spring Boot app to NodeJS[…]

Scrum Master certification (PSM I) cheatsheet

Recently I got the Professional Scrum Master certification (PSM I) with a score of 100%. Here I present the steps I followed to prepare for the exam and some tips that will help you pass it. The Scrum Master Certification exam The Professional Scrum Master certification (PSMI) exam consists of 80 questions that need to Read more about Scrum Master certification (PSM I) cheatsheet[…]

Java Concurrency using Fork/Join Framework

The Fork/Join Model is a parallel design pattern that sets up and executes concurrently code parts. The execution divides in parallel at multiple points in the program, performs a task in parallel and later it joins at a single point. In java it is implemented by the Fork/Join Framework, an implementation of ExecutorService interface, that Read more about Java Concurrency using Fork/Join Framework[…]

Test Javascript/Angular functions during the Maven Lifecycle

The application we will work on, is a Spring and Angular web project, which is built using Maven. In order to import Angular and the rest front end libraries and frameworks, we use Webjars, a technology that allows us to package the client-side web libraries into Jar files. In the modern web applications, more and Read more about Test Javascript/Angular functions during the Maven Lifecycle[…]

Instalike – Use selenium for Instagram account promotion.

This project uses Selenium and Quartz scheduler to repeatedly like a specific amount of Instagram photos. We can configure the number of photos we want to like each time, how many times the application will run, the time interval between each run and the hashtags that we want to like photos from.  Using Selenium, we Read more about Instalike – Use selenium for Instagram account promotion.[…]

Using Observer Pattern to send messages in a Spring project

In this post we display a usage of the Observer pattern in a Spring project. We need to push a notification to a user, based on some other user actions. We will use a simple action like a dropdown selection. When a user chooses an option from the dropdown, the rest users will get notified Read more about Using Observer Pattern to send messages in a Spring project[…]

Spring Security Advanced Authorization

In this post we implement some more advanced authorization practices. We already showed in previous post how to use Spring Security to setup access control in one page based on user roles. Here we will show how we can extend this authorization with security tags and method security. This post follows Spring Security Simple Authorization but adds Read more about Spring Security Advanced Authorization[…]