JDriven Blog

Inhale, exhale, release

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Jacob van Lingen

In the modern western world, a watered down version of Haṭha yoga is becoming more and more populair. Many describe the focus on physical posture and breathing techniques to be both pleasant and calming. In everyday’s world of stress and deadlines, a moment to relax and release can come for some not often enough. If you ask your common developer about ‘release’ though, chances are high they do not talk of relaxation but of stress and hard work. I was thinking about this when I wanted to release a Gradle based Java FP library I am writing for my specialization.

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How tech culture can contribute to growth

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Erik Pronk

In my last blog How tech culture can contribute to quality I focused on how passion and motivation builds a tech culture. This helps people develop themselves in a positive way while organisations are more successful in delivering high quality solutions. So basically everyone wins. In this post I want to dive into how we can help educate the community in a way that they understand not only what to do with certain knowledge, but also why things work in a specific way.

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Configure Hikari Connection Pool when using AWS RDS IAM

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Tom de Vroomen

Amazon Web Services offers a way to connect to a MySQL or PostgreSQL database without having a password, instead an authentication token can be used.
Within AWS this type of authentication is called RDS IAM.
Users don’t need to store an username and password and credentials don’t need to be stored in the database, which makes this a secure authentication method.

So, this makes it interesting to use this in your Spring Boot application. Spring Boot will use a HikariCP connection pool by default, but HikariCP 4.0.3 doesn’t support the use of authentication tokens.

So, how do I make this work within my Spring Boot application?

  1. Enable RDS IAM for your database

  2. Create a custom Hikari DataSource

  3. Update application properties

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Create a Docker image running Robot Framework

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Justus Brugman

Robot Framework is easy enough to set up. When you have Python installed on your system, it can be as easy as running pip install robotframework && pip install robotframework-appiumlibrary. This is not how I want to do it. For this intro, I want to run the Robot Framework in a Docker image.

Robot Framework is a generic open source automation framework. It can be used for robotic process automation (RPA), and also for acceptance level testing and acceptance test-driven development (ATDD). In this blog I want to focus on the first steps to start working with it.

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Register your Avro Schemas in Production with Schema Registry Maven Plugin

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Tim te Beek

Apache Kafka is often used together with Confluent Schema Registry, as the schema registry allows you to store and retrieve your Avro, JSON Schema and Protobuf schemas for Kafka message (de)serialization. By storing a versioned history of schemas for topic values, with configurable enforced compatibility, you ensure producers and consumers can continue to exchange compact serialized messages even as schemas evolve.

By default, client applications automatically register new schemas. If they produce new messages to a new topic, then they will automatically try to register new schemas. This is very convenient in development environments, but in production environments we recommend that client applications do not automatically register new schemas. Best practice is to register schemas outside of the client application to control when schemas are registered with Schema Registry and how they evolve.
— On-Premises Schema Registry Tutorial
On Auto Schema Registration

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Java Joy: Run Action When Optional Value Present Or Not

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Hubert Klein Ikkink

If we have an Optional instance we can consume the value if it is present using the ifPresent method. Since Java 9 the method ifPresentOrElse has been added to the Optional class. The first argument is of type Consumer and is invoked when there is an optional value. The second argument is of type Runnable and is executed when the the optional is empty. The method in the Consumer and Runnable implementations does not return a type but returns void. Therefore we should use ifPresentOrElse when we need a conditional side effect for an Optional instance.

In the following example we have a method handleName that will update a list if an optional value is present or increases a counter when the optional value is empty:

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Clojure Goodness: Turning Map Values To Map Keys

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Hubert Klein Ikkink

In the clojure.set namespace we can find the function map-invert. This function returns a new map where the values are keys with the appropriates keys of the original map assigned as value. If the original map has duplicate values than the latest key for the duplicate value will be the value of the new key.

In the following example code we see the result of using map-invert:

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Spicy Spring: Splitting Configuration and make Properties immutable

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Willem Cheizoo

A Spring Boot application typically consists of several components handling the business functionality and probably some configuration to configure all these components. This configuration consists of defining some properties, setting up some beans with the right conditions and dependencies and wrapping it all together into a class structure. Nevertheless, the configuration of our Spring Boot application is also code. Let’s threat is as code.

In this blog we will se how we can improve our Spring Boot Configuration by splitting up the configuration from the properties and how this effects the design principles.

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