Introduction

While building microservices one would always think of creating a resilient system. Especially when the service has an external dependency to an API or datasource and its availability in the lower environments is questionable.

Another scenario would be when we want to take a different course of action if a certain kind of exception is thrown from the external system.

In a Microservice architecture, we can implement the circuit breaker design using any of the popular implementations. The two most popular implementations are provided by Netflix as Netflix-Hystrix and Alibaba as Alibaba-Sentinel.

Both the implementations provide the basic features needed…

Spring boot annotations make project configuration very easy and starting a project hassle-free.

But there are times when these annotations are used incorrectly.

Let’s go through a few of them and understand how to use them effectively.

1. @SpringBootApplication

This annotation is an equivalent of all the three annotations mentioned in the below list. If you are using the ones mentioned below, then do not use SpringBootApplication annotation.

These annotations are not mandatory so you could use them based on the features your application needs by default.

2. @Validated

Validated is often confused with @Valid annotation which belongs to…

The first time I touched a keyboard was in school, we were all given one chance to play a video game, and when the prince dies in the game, hand over the keyboard to the next Student in line. I just played it once and as it was an optional class I never went back to that room.

Later in high school, I enrolled in a crash course on Microsoft Office. It was fun for the first couple of days but then I was bored to death. How much can you tolerate MS Office right?

Later I got my bachelor's…

What is Brave?

It’s a browser, just like chrome, firefox, safari, and others. We can browse, watch youtube, read blogs and do everything one would normally do with chrome or other popular browsers.

Brave uses V8 javascript engine, the same engine that is used by chrome and Node.js.

Brave was founded by Brian Bondy and Brendan Eich, who is also the creator of Javascript and co-founder of Mozilla Corp in 2015.

How is Brave different?

Brave removes all the ads and ad tracking elements while loading the web page, replaces them with a few of its own advertisements (based on…

In this tutorial, we will learn to implement a simple SpringBoot application that implements the CQRS principle.

We will use Axon 4 framework in this use case. To store events, we will use Mongo DB, and instead of a repository to store and query data, we will use a static Map.

Concept

CQRS — Command Query Separation. In simple words, either perform an action on the data or query and return the data.

Axon is an open-source Java framework to develop event-driven microservices. Axon comes with Axon framework and Axon server. …

In this tutorial, we’ll walk through a simple implementation of the hexagonal architecture. Alistair Cockburn proposed this concept in 2005.

This architecture is also called “Ports and Adapters” and “Object Structural”.

We’ll go through the concepts first and then learn the implementation of this architecture using Java.

Concept

Hexagonal Architecture defines that an application’s business logic should be isolated from the external applications.

Based on this concept, we can divide our application into 3 parts. The business logic will be the inside of an application. The user and server sides of the application would be the outside of an application.

Implementation

Let’s…

Java never lost its popularity despite tough competition from a number of cool and new languages. It's a language that’s loved by technology giants as they expand their business according to the growing demand and look for a stable and scalable backend solution for their mobile and web applications.

With the rise of Python and Javascript for backend development, people did question the ability and role of Java in the emerging markets but the good news is — Java is here to stay.

Before we figure out the relationship between Java-5G-IoT, let's just refresh our memory on these latest technologies.

IoT (Internet Of Things)

…

So I have been busy learning cryptocurrencies and blockchain for the past couple of days. It's interesting, challenging, and fascinating stuff.

The more I learned the more I was confused as to how are these things getting so popular?

Like we understand stocks, it’s basically companies that build and sell products or sell services and we value them and want a share of it and the share price increases. …