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Rancher and Grafana – A long case-study to learn some DevOps

Motivation Cryptotrading is so cool and profitable these days… So I decided to try it out. But if you want to do something well, you need a lot of information and tools. I wanted some visualization, with chat (Slack) integration, and some alerting tools/bots. This post will describe the tools I found and started playing […]

Push Notifications – a bigger picture

Many applications we create require the ability to send push notifications. Sometimes we are the ones who made the client and the backend side as well. The available tutorials are helpful but not always entirely clear; we met quite a few challenges. Let’s look at a specific example. –          We’d like to send a push notification from […]

How to make a custom Username Password Authentication Filter with Spring Security

  Introduction Basically I’ll show you how to use Spring Security and how to customize it if you want. First we’ll implement the basic authentication with basic responses and other stuff, and I’ll show you how to customize the login and logout process as you wish  Simple Authentication After you added the required dependencies described on Spring’s website, […]

Ray Tracing with Akka – Part 4

Where did we stop last time? Read the first part of this series for an intorduction to ray tracing and what I wanted to achieve. Here we created a sphere and a shadow. Read part two for a discussion on creating a plane and letting our objects reflect and refract. Part three has been the most advanced, in here we built […]

Easy open source licenses

A simple description of open source licences so you’ll know how to use them The Open Source Community and Licenses The open source community creates and uses free software. A copyright ensures that the author possesses exclusive rights to their product. With a licence the copyright holder provides the rights to study, change, and distribute the software to […]

Spring & Multiple SQLs: How to easily connect your Spring application to multiple SQL databases

This post will show you how to connect your Spring application to multiple SQL Databases at the same time. But first, let’s see when multiple DB connections are useful. For example you have an application and you have that application set up in different environments (let’s call it “prod app”), and you want to write […]

Ray Tracing with Akka – Part 3

Where we left off In the last two posts, we reached the capabilities of a simple ray-tracer. We now have two types of shapes (sphere and plane), we can calculate shadows, reflections and refractions recursively. Before we move onto the more computation-heavy shapes, I am curious about how I could move our computations to separated nodes. So […]

Using Websocket on Android

This post is the sequel to this post about WebSockets. I know what you are thinking. But why? Using WebSockets is a really useful way of building realtime applications, because they provide a fast, full-duplex communication channel between the server and the client. There are many libraries out there, usually providing straightforward, easy-to-use APIs for developers […]