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Oracle database is a Relational database developed by Oracle, Oracle DB provides high performance with failure recovery features, easy to manage the database, and has a good reputation for supporting Enterprise level applications. For you database admin or software developer that are newly using Oracle database, you can follow this simple get started guide. Follow each one of the instructions from installation to launch and create a new database table. Download and install Oracle DB Download the oracle database express edition from the following link : https://www.oracle.com/database/technologies/xe-downloads.html When the installation process is running, then you should set the default password that you will use for login. Login using SqlPlus Open terminal or command prompt and type "sqlplus”. Then enter the username SYSTEM and password you choose on the installation step earlier. Create new user Before the SYSTEM user can create new user, you have to execute this command: alter ...

Reactive Spring Logo This is maybe a very simple task, but for those of you that may not be familiar with WebFlux found it difficult to create a Rest API that handles upload and download in Reactive spring application. Create the skeleton Spring project Create a new project, go to start.spring.io , on the dependencies section, add Spring Reactive Web. Generate and extract it into your desired project location. Instead of using spring-boot-starter-web, use spring-boot-starter-webflux instead in your pom.xml. Here’s the pom.xml for our Reactive Rest API project. Create our Rest controller Now that you have set to use WebFlux instead of the usual web, we have to change a little bit in the Controller class that handles the API endpoints. It doesn’t change much but you have to wrap the Response in Mono and the request parameter to FilePart. So our upload and download file controller will look like this. Create utility to handle file upload We need to structure our project better, so we cr...

Microservice Spring with Apache Kafka Today, I want to share how to use Kafka. It's quite interesting once you get the hang of it, and I hope my explanation will make it a bit easier for you. So, Kafka is primarily known as an asynchronous messaging queuing system. This means it allows different parts of your application to communicate with each other without waiting for immediate responses. However, there are times when you might need a more immediate reply from another service in your project. Luckily, Kafka can handle this too. Here’s how it works: The client side sends a message to the server side via Kafka. This message includes a special identifier in the Kafka header request, known as KafkaHeaders.CORRELATION_ID, along with a topic where the server should respond. The server, after processing the request, sends a message back to the same topic with the same correlation ID. This way, the client knows that the message is a response to its initial request and can act accordingl...

Blogger with laptop - Image by Peter Olexa from Pixabay Today’s is not going to be a technical tutorial about how to do stuff in some programming language or fixing some bug in some programming technique. It’s just my overall view about blogging without any preparation or research, it’s purely written straight from the document editor. As I am now a self-proclaimed tech blogger, because I feel I have written enough articles to have myself categorized as a blogger. I will be giving some advice about writing a tech blog, but this is for beginners. So, if you are not a beginner, maybe this is not the right article for you. Consistency Writing a blog is not easy, in fact it is very hard that every beginner will leave their blog untouched after a few tries writing less than 20 posts. For me the hardest part of writing a tech blog, or any other niche blog is the consistency, because we don’t always have perfect time, or perfect mood to develop a written article. To be consistent writing on ...

ACID principle in SQL database ACID  is a set of principles whose acronym is Atomicity, Consistency, isolation and durability. As any other principle, it’s done by the developer or database admin or available feature on the database system of choice (MySQL, Postgres, SQL server). So as a developer or data admin you must know this principle in order to design and develop a database system for your project. Dealing with database transactions that have many queries in it should be handled following the ACID principle. When a set of queries are executed ACID prevents disaster in your data because something that is partially error in the middle of transaction can lead into data inconsistency. Because the app query expects all the query should be completed with no interruption, sometimes your database depends on other data. So here’s what ACID principles acronym are: Atomicity All queries in a transaction are treated as a single thing, if one query fails, the whole thing shouldn’t change...

Job Interview - Image by Sue Styles from Pixabay If you are a software developer currently looking for a job, these are some common questions that the interviewers usually ask you. So, you better prepare. The question in the interview process will range from basic to technical questions. The basic questions will assess your experience in your previous job. If you are just a fresh graduate, you just have to tell them about the internship and your contribution. If you are already working in a company, again the principle to answer all the questions is the same, just share your contribution on the team of your company that you work before. In my experiences applying for a software developer job, there’s not going to be tricky questions actually, it rarely happens. Tell me about yourself? This question is simply asking your experiences in the software development industry, just it, nothing else. To answer this question, you need to tell in detail what’s So as relax as you can, tell the in...

While writing our codes in Java is easier done using specialized Java IDE (integration development environment) like Eclipse, VS code, IntelliJ, there’s actually no requirement to make your java application. You can just write the code using any tools. The advantage of writing codes in a simple editor like notepad is the lightness of the program, when writing codes in IDE it just feels sluggish when we are typing on it. Because in Notepad, you won’t be given any code suggestions, like method, variable, class etc, so you are typing faster. It can be cumbersome for new developers writing java code in a simple editor, but it is worth a try. So, let’s do it. 1. Install notepad++ We are not going to use the default windows notepad, it’s too ancient to do basically anything, so let’ s just give you the improved version of notepad, the notepad++. You can download from the web official download page here https://notepad-plus-plus.org/downloads/ . 2. Create spring boot skeleton app Go to the pa...