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Keeping a project competitive within the technology market is, without a doubt, one of the most significant challenges for engineering teams. It is because it is necessary to update and revise solutions constantly: since, in the same way, it is terrible to use legacy technologies, it is also not advisable to use technologies simply because they are...
Managing user experience is pivotal for software development. Test automation enables user preferences and convenience to remain at the center of the development process while saving time and effort. That is why comprehensive automation testing has become necessary to retain customers and meet their expectations. With significantly shorter time fra...
In this Spring Boot video tutorial, we take a closer look at the JUnit Integration Test and testing JWT Tokens and UserID (RESTful Web Services). Let's get started!
Since Java 5, the core Java APIs have been enhanced with more features for handling coordination between threads in concurrent programming. In this post, we discuss a class in the java.util.concurrent package that aids in this purpose: the CountDownLatch. Introduction The CountDownLatch class enables us to coordinate threads by introducing awarenes...
In this Spring Boot/RESTful Web Services video tutorial, we take a closer look to find out what H2 in-memory database is and why to use it. Let's get started!
More than a decade ago, I wrote about the DTO: A data transfer object is an object that carries data between processes. The motivation for its use is that communication between processes is usually done resorting to remote interfaces, where each call is an expensive operation. Because the majority of the cost of each call is related to the round-...
In the video below, we take a closer look at the Spring Boot Testing Service Layer Code with JUnit 5 and Mockito (RESTful Web Services). Let's get started!
One of the scourges of corporate life was the forced monthly password change. As anyone who understands security will know, this was always a terrible idea - it leads to a culture of passwords that are weak, formulaic, and written down.Another, more widespread scourge, is the use of devious complexity requirements.Fortunately, the world is changing...
In the video below, we take a closer look at Spring Boot, with a focus on testing RestController methods with JUnit 5 and RESTful web services. Let's get started!
This article explores the challenges in developing a graphical user interface (GUI) for Financial Information eXchange (FIX) data. FIX is both a protocol and a message format, but to create a FIX GUI we will focus just on the message format. A FIX message is a standard message format for transmitting financial and investment banking data. Below is ...
In the video below, we take a closer look at Spring Boot and update user details in an API test client using REST Assured. Let's get started!
I have been posting multiple videos about the Performance Engineering Series on the QAInsights channel, which will help you to get started with troubleshooting Java applications. In this blog post, we are going to see how you can use Eclipse Jifa to identify potential performance bottlenecks in your Java applications. Let us get started. Eclipse Ji...
Last week I went to Cloud Expo Europe at ExCeL.(Yes, there was a tube strike. No, that didn't affect me much. Had to walk from London Bridge Station to Tower Gateway to get to the DLR, but walking past HMS Belfast, Tower Bridge, and the Tower of London isn't such an imposition.)Now, "Cloud Expo" is the umbrella event. There are a number of co-locat...
In the video below, we take a closer look at Spring boot- Get user details API Test Client using Rest Assured | API automation using Rest Assured. Let's get started!
Estimating Allocated Memory (Not Object Size) Previously, I explained how to calculate an object's size considering OS binary or types of objects and primitives. In this article, I'll only review ways to estimate the size of already allocated memory for a given object. There are a couple of ways to do it. Here we review the most popular. Estimating...
In the video below, we take a closer look at Spring Boot's Get User details, API test client, and API automation using Rest Assured. Let's get started!
Overview In this tutorial, we are going to explore the possibilities of generating method builders with Lombok's @Builder annotation. The aim is to improve usability by providing a flexible way of calling a given method even if it has a lot of parameters. @Builder on Simple Methods How to provide a flexible usage for methods is a general topic that...
We take a closer look at creating user API test clients using REST Assured a Spring Boot API automation using Rest Assured. Let's get started!
In the following Spring Boot video tutorial, we take a closer look at the User Login API Test Client and API automation using Rest Assured. Let's get started!
FOSDEM took place February 5-6. The European-based event is one of the most significant gatherings worldwide focused on all things Open Source. Named the "Friends of OpenJDK", in recent years the event has added a devroom/track dedicated to Java. The effort is led by my friend and former colleague Geertjan Wielenga. Due to the pandemic, the 2022 ev...
Blockchain and Java: Are They Comparable? In simple terms, blockchain is a special distributed network and Java is a programming language. So how we can compare it? Does it seem that we can't? Wait a Minute! There Are Still Many Similarities They are different, but they have many things in common or that are similar between the two. Blockchain netw...
Classical Singleton Introduction Classical Singleton is one of the most well-known structural patterns. It is widely used in production and is responsible for creating only one single instance. This pattern was mentioned in the GOF patterns book. How is it possible that it became an antipattern? Before we start, let's remember what a classical Sing...
In the video tutorial below, we take a closer look at the double-checked locking design pattern in Java. This tutorial includes an introduction, implementation, and out-of-order writes. Let's get started!
In this video tutorial below, we take a closer look at Messaging Design Pattern(MDP) in Java. This tutorial includes an introduction and implementation of a proxy, adapter, and web service. Let's get started!
In the below video, take a closer look at Spring boot- delete user details API test client using Rest Assured. Let's get started!
There are things you can do in Java you rarely see, generally because there is no use for it. However, there are some unusual things in Java that could be surprisingly useful. Chronicle Software uses a number of different usual patterns in its low-level libraries most developers wouldnt generally come across.
Preface The iText 7 is a powerful library for PDF manipulation. This article is the third one in the dedicated series to the iText library. The previous articles in this series are: Introduction to iText 7 Using Barcodes in iText 7 There are several articles for adding a watermark into PDF (e.g. https://kb.itextpdf.com/home/it7kb/faq/how-to-...
When we group elements from a list, we can subsequently aggregate the fields of the grouped elements to perform meaningful operations that help us analyze the data. Some examples are addition, averages, or max/min values. These aggregations of single fields can be easily done with Java Streams and Collectors. The documentation provides simple examp...
In this video tutorial, we take a closer look at Object Relational Behavioral Design Patterns in Java. This tutorial includes an Identity Map, Unit of Work, and Lazy Load. Let's get started!
When we build a microservice architecture and the number of services keeps growing, we face the problem of debugging and tracing requests through our entire system. What happened when a user got a 500 error on his request? What service incorrectly processed his request? All these questions can be solved by the Distributed Tracing System. Let's take...
Introduction In this article, we will learn about chat options between two people, including how they can share texts with each other. The application needs to have instant messaging so once a user sends the message to a friend over the application, the friend will receive the push notification at the given time. The quintessence of an app like th...
In the video below, we take a closer look at Session State Design Patterns in Java including the client, server, and database session state design patterns. Let's get started!
Introduction I just published the 3rd episode of the "140 Second Duckling" tutorial series and I'm getting into the rhythm of doing them. I posted the 2nd episode last week and in this post, I'll dig deeper into both. I tackled a lot of basic stuff about debugging but I picked two big headliners that a surprising amount of developers aren't famili...
ID generation in the client instead of the database is the only option for distributed apps. But generating unique IDs in such apps is hard. And it's essential to generate them properly because JPA will use IDs to define entity states. The safest option is to use UUIDs and Hibernate's generators, but there are more options starting from custom gene...
In the video below, we take a closer look at Domain Logic Design Patterns in Java including the transaction script, domain model, table module, and service layer. Let's get started!
In the video below, we take a closer look at Bridge Design Pattern in Java including an intro, real-time examples, a class/seq diagram, and an implementation. Let's get started!
Ever since Java 8 introduced default interface methods, I felt there had to be a way to use it for multiple inheritance. I have never needed it, but I was bored for a bit today, so decided to try the following idea: Create a non-public class XData to hold the fields the interface needs to work with, and a public interface X in the same X.java sou...
A couple of years ago, I developed an application in Kotlin based on Camunda BPMN to help me manage my conference submission workflow. It tracks my submissions in Trello and synchronizes them on Google Calendar and in a Google Sheet. Google Calendar offers a REST API. As REST APIs go, it's cluttered with String everywhere. Here's an excerpt of the ...
In the video below, we take a closer look at distribution design patterns in Java - Data Transfer Objects (DTO) and remote facade design patterns. Let's get started!
In the below video, we take a closer look at Object-relational structural design patterns in Java. Let's get started!
In the video below, we take a closer look at the Proxy Design Pattern in Java. This video tutorial includes an introduction, real-time examples, a class/sequence diagram, and implementation. Let's get started!
I'm pumped to announce that the Angular Mini-Book 2.0 has been released! You can download it in PDF and EPUB formats from InfoQ. About this book The Angular Mini-Book is a guide to getting started with Angular. You'll learn how to develop a bare-bones application, test it, and deploy it. Then you'll move on to adding Bootstrap, Angular Material,...
Probably the biggest breakthrough while Unit Testing is to realize that writing tests offer priceless feedback about the design of your production code. This feedback goes from suggesting immediate obvious improvements, up to hints about some of the most advanced design principles in software engineering. This article briefly enumerates these hints...
Complex logic should be implemented on data structures you have full control on an internal Domain Model that you can tailor to your problem to simplify your code. Here is an (opinionated) list of term definitions used in this article:
In the video below, we take a closer look at the Decorator Design Pattern in Java. This video tutorial includes an introduction, real-time examples, a class/sequence diagram, and implementation. Let's get started!
The dw::core::Arrays module has some nice functions that works with arrays. One of these functions is countBy. The function takes an array as first argument and a predicate function that accepts an it...
In this article, we will learn how we can do the following: Generate a valid certificate for free Configure a Spring Boot app with it Renew it when it expires In my previous blog post, we became familiar with the configuration of a Spring Boot Application with a self-signed certificate. Self-signed certificates are good for specific purpos...
Object-Oriented programming refers to the concept in high-level languages, such as Java and Python that uses Objects and classes in their implementations. OOP has four major building blocks which are, Polymorphism, Encapsulation, Abstraction, and Inheritance. There are other programming paradigms, such as Procedural programming in which code is wri...
When I was working in software development back in the 1990s, nearly all the software libraries that I worked on made use of event loops. This was because at the time most hardware had just one single CPU. Back in the day, I remember the excitement when threads were introduced into our development framework. It was revolutionary that we could now r...
OpenJDK is the development kit for Java, the language with 26 years of history behind it. It is not a new language by any standards, especially in the industry where new solutions appear every few years and are usually better than their predecessors. And OpenJDK, the most popular instance of Java, is 14 years old already. By all means, OpenJDK shou...
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