Suppose you are testing a set of Quarkus based microservices. They run as Docker images inside a Kubernetes cluster on your local machine, e.g. using MiniKube or Rancher Desktop. At some point you find a bug in one of the services, or you find that you need an extra logging in code. Now you would like to quickly modify the code and redeploy it in your Kubernetes cluster. Typically your Docker image is build using a build pipeline on a build server, which may take several minutes. Can this be done any faster and easier? With Skaffold you can!

Many social media automation platforms now charge for automatically posting an RSS feed to X.com (Formerly Twitter). One alternative to paid social media automation platforms is to use Slack. If you are already paying for Slack Pro this comes at no additional cost. In this post we will have a look at setting up a Slack platform app to post our JDriven blog RSS feed to X.com.

Java 21 the new Java LTS (Long Term Support) is out and as a tribute to it I wanted to write a blog about it on the 21th day of Blogtober. What is new and which features are in it for me as a developer? I’ve taken a look at the release note from java release 18, 19, 20 and 21 and here is small summary of some new features. In this blog I only cover final released features and will exclude the features that are in preview or incubator.

Recently I stumbled upon an example of why managing your dependencies in a maintainable way is important. The issue I had was in a multi-module project where individual Maven dependencies were overridden everywhere, the result was that a lot of dependencies were in conflict and upgrading these dependencies became quite troublesome. One of the countermeasures for me was the use of certain Maven Bill of Material (BOM).

With using a BOM I only had to set version of dependencies once and did not have to duplicate the dependency in the parent because the bom implicitly has it already.

There are plenty of ways to build software that responds to changes in data or outside events. It can be less intuitive to come up with a solution that needs to respond to nothing happening.

jq is a powerful tool to work with JSON from the command-line. The tool has a lot of functions and operators that makes our live easier. One of the operators we can use is the alternative operator // which allows us to specify default values. If the value on the left side of the operator // is empty, null or false then the value on the right side is returned, otherwise the value itself is returned. The operator can be used multiple times if we want to have multiple fallbacks for a value we are checking.

With simple ZIO layer creation, it’s convenient to use +`, `>>>` and `>> to compose layers.

When layers and dependencies get more complex, ZLayer.make is there to help.

We were promised that microservices would make our software more stable and easier to scale horizontally. But the added complexity often creates a lot of shared code and complex infrastructure. Dapr promises a solution by placing these cross-cutting concerns outside your code.

Kotlin’s standard library offers many functions, but the ones that stand out in my opinion are scope functions. These scope functions exist to execute a code block in the context of the object on which you execute it. Within this scope, you can perform operations on the object with or without a name. Scope functions can make code more readable and concise, but beware! Nesting scope functions can cause confusion about the current context object.