In today’s fast world, everybody wants to use applications with a response time as little as possible. Redis is mainly used as a cache and it helps developers achieve high performance in their applications. This tutorial will show how to easily set up a Redis instance using Docker, demonstrate main datatypes, and examples of CLI commands. — The setup The easiest way to create an instance of Redis locally is by using Docker and Docker Compose. To be able to create the docker container with Redis we have to create a definition file in yaml format called a docker-compose file. But I will present this file a little bit…

Application performance is essential. As a web application developer, I do everything to guarantee that my code will run fast. One of the offenders of the application response time is communication with a database. Offen during development a small amount of data is used to test the code. But when…

We as programmers have to guarantee that our code works even when it encounters exceptional situations. When using asynchronous and parallel processing the exception handling process differs from one in synchronous sequential code. This tutorial is about exceptions in the Java CompleatableFuture and how to handle them. — Use case Let's say we have a Java Spring Boot web application that manages information about customers and their purchase transactions. It has REST APIs that return information about a customer by its ids such as an id, a full name, phone number, creation date, and a list of purchase transactions. To…

When Java 8 was released developers got many game-changing features. Among them was a CompletableFuture a significant improvement in parallel and asynchronous processing. In this tutorial, I will show you how to take advantage of this feature, which makes code faster and more responsive in Spring Boot. — Use case For a better understanding of how CompleatableFeaure works, we will have the synchronous code and then we will refactor it to use CompleatableFeature.

This tutorial is intended to help understand better how Java LinkedList works. The best way to do it is by creating this data structure yourself. So in this tutorial, we will make our simple linked list. — What is a linked list? The linked list is a data structure consisting of nodes. A node is the smallest unit of a linked list and it contains the value and the address (reference) to the next node. The linked list has 3 different types of nodes, a simple node mentioned before painted white in…

By writing this tutorial I don’t want to “reinvent the bicycle”, this tutorial is not an attempt to rewrite the famous ArrayList class. The purpose of this tutorial is to “learn by doing”. By creating the resizable dynamic array from scratch you will have a better understanding of the internals of this type of data structure which will significantly improve your skills. — Defining the contract by interface

The array is a cornerstone of Java language. It is a simple yet powerful data structure. This tutorial is about the basics of arrays in Java that every developer should know. — 1. Brief introduction Let's define what an array is. An array is a container with a fixed number of “cells”, each containing a value of the same type. This container has a length (capacity), size, and indexes. The capacity of an array is the quantity of “cells” the array has. And the size…

MongoDB is a NoSQL database that is a leader in its class. It is popular because it is fast and at the same time stable and highly available. This is achieved by employing replica sets. This tutorial is about creating a replica set locally just with one command. — When we have only one instance of a database our application is vulnerable. It is because when this instance will crash we don't have a second option and our application will crash too. Another problem of using only one instance can arise when we have heavy use of the database…

Nowadays we have the privilege to run programs on computers with multicore processors. As a result, applications run faster, can process a larger amount of data, and they are more responsive. At the same time, we have to be careful when running our code on the Docker containers. Depending on the configuration, using multithreaded code may do more harm than good. — Containerized applications. Most of the developers including me use “entire” PC to run and test the code. When I say “entire” I mean that our code uses all available resources of the computer. In the era of microservices, most applications are containerized and run on the cloud. The most popular tool that…