JCore Blog

Expanding the Java Bean Validations

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Jacob van Lingen

Since beginning of time mankind has been looking for a way to separate right from wrong. Where the primeval man judged righteousness by the contributions of the tribe, the current day programmer judges right by the wishes of the customer. For many years the average programmer wrote a bunch of logic to check if the boundaries defined by the client where uphold. As time went on and programming languages involved, metadata could be added to enrich functions, methods, classes and the like.

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Visualizing a nasty virus

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Jacob van Lingen

At the time of writing the coronavirus is raging the earth. Very soon after the outbreak, visualizations of both the virus and the effect of the disease started to appear everywhere. As I partially graduated in the subject of data visualization, I have always been interested in those graphs. Lately, I followed an introduction course to visualize data with D3.js. After I completed this course, I wanted to draw some meaningful graphics with this library. So follow along when I explain a little bit about D3 and then draw a simplified version of the coronavirus molecule.

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Don't be afraid of Docker

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Jacob van Lingen

As a developer, you are familiar with Docker. You push your images to the Hub, use Compose locally and know a thing or two about Kubernetes. Or…​ Well…​ To be honest…​ You don’t. And you are ashamed you don’t know anything about it. You browse the internet and it’s so overwhelming. So you stop looking and continue what you’ve been doing all the time. Deep inside, you still wonder. Can’t anyone not just explain Docker in simple terms? Is it really this hard? Or am I just missing something really obvious?

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An introduction to Reverse Shells

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Niels van Nieuwenburg

In my last blog I gave you a small introduction into the term "Reverse Shell". I described it as: "A Reverse Shell is where your target machine creates a connection to your machine, after which you get a shell on the target machine in which you can execute system commands." It is similar to SSH, but without any encryption and the connection is created the other way around (from target to you, instead of you to the target).

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How an interactive shell can make your life easier after getting a Reverse Shell

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Niels van Nieuwenburg

At JCore, we follow a three year program to become senior developers. After following this program successfully, you will be promoted to the JDriven company. In the final year, we have a specialization in a topic of our choice. I chose to specialize myself further into security. I have been studying this topic for some time now, even contributing to the fast track courses as a security teacher. Until now, most of my time I spent on the defending side and now I want to take a look on "the other side". So my specialization is all about attack, also described as joining "The Red Team".

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Maintain your local AWS environment with Commandeer

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Thomas de Groot

In my previous blog about Running AWS locally with LocalStack I’ve shown you how to use Localstack, a tool to mock your AWS environment on your local machine. When working with Localstack, I always had to prepare the environment for my application to run. Most of the time this could be done automatically via scripts, but some preparations, for instance editing some data in a S3 bucket, could become a little tricky.

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Running AWS locally with LocalStack

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Thomas de Groot

More and more companies are switching over to cloud native environments. As a developer this gives me a lot of services to create awesome applications. The challenge that occurred to me right away was how to use all those new components during development, since some companies do not have a testing/development environment in their cloud provider to play with. LocalStack piqued my interest to simulate an AWS environment locally on my laptop, or when running the CI/CD pipeline.

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