How to enable high DPI mode in Firefox

In our days High DPI monitors become more popular. But unfortunately, still there are issues with some applications on such monitors mostly on all operating systems. �And Firefox on Linux is not an exclusion. All what is written bellow mostly relevant to Firefox on Linux, because on Windows and Mac OS Firefox looks good out of the box on high DPI monitors. Right now (when I’m writing this) in Linux only KDE can scale monitors out of the box. Continue reading

How to run Spring Boot and MongoDB in Docker using Docker Compose

Into the previous post How to run Spring Boot and MongoDB in Docker container I described how to start Spring Boot web application and MongoDB in docker using Dockerfiles. Described approach works, but has some drawbacks: we need to remember all commands and repeat them from time to time. Into this tutorial I’ll describe how to build locally a Docker image with Java application and run it together with MongoDB in Docker containers using Docker Compose. Continue reading

Linux: how to make Bluetooth working

This post describes step by step solution of how to make Bluetooth working on Lenovo V580c in linux distributions: Ubuntu 17.10 and Manjero 2017. My Lenovo laptop uses BCM43142 chipset. Find bluetoth chipset and device ID First of all we need to make sure that we have appropriate Chipset. Open terminal and enter the following command: lsusb | grep Bluetooth The output will look like: Bus 001 Device 004: ID 105b:e065 Foxconn International, Inc. Continue reading

Scala expressions and definitions cheatsheet

Intro This is a cheatsheet of Scala expressions and definitions from Coursera online course Functional Programming Principles in Scala What is Expression Expression is any bit of Scala code that yields a result. In other words expression evaluates to a result or results in a value Categories of expressions An identifier such as x, isValid A literal, like 0, 2, abc A function application, like sqrt(x) An operator application, like -x, x+y A selection, like math. Continue reading

VSCode: How to change the font size

Visual Studio Code is a lightweight but powerful source code editor which runs on your desktop and is available for Windows, macOS and Linux. It’s developed by Microsoft. Here a guide how to change the Editor’s font and the font of the hole application (tabs, explorer, etc). This article describes how to change the VSCode’s fonts. How to open setting There 2 way of opening VSCode’s setting: Over main menu or hot keys: go to File -> Preferences -> Setting (or click on Ctrl + Alt + S) Over setting. Continue reading

Principles of Object Oriented Design

Intro Here is a list of main principles of Object Oriented Design (OOD) with short description of them. I’ll provide detailed descriptions for some of the principles in later posts. OOD principles can be divided into two groups. The first group well known and named SOLID (has 5 principles) and describes class design. The second group (6 principles) is related to the packaging of the application. Principles from these group describe how package and component design helps us to organize large application into packages or components. Continue reading

Partitioning in Relational databases

Introduction Partitioning is a process of dividing a table into multiple smaller pieces, where each piece of such a database object is called a partition. This tutorial describes what is Partitioning and provided an example of Range partitioning in PostgreSQL database. Benefits of partitioning Query performance could be increased when: most of the heavily accessed rows of the table are in a single partition or a small number of partitions. queries or updates access a large percentage of a single partition because of sequential scan of that partition instead of using an index and random access reads scattered across the whole table Seldom-used data can be migrated to cheaper and slower storage media Performing maintenance operations on one or more partitions can be made more quickly. Continue reading