Things You Might Don't Know About Micronaut Framework
Are you looking for a collection of code snippets showcasing interesting and useful features of the Micronaut Framew...
3 posts
2022
These 10 New Features Make Groovy 4.0 AWESOME!
Sealed types, switch expressions, and record types. Here are just a few new features introduced in the latest Groovy...
How to generate a random password in Groovy?
Sometimes you need to generate a random password (or just random string of any kind.) Today I will show you how to d...
17 posts
2020
Merging JSON files recursively in the command-line
Have you ever need to merge two (or more) JSON files and you wondered if you can do it in the command-line? In this ...
Jenkins Declarative Pipeline with the dynamic agent - how to configure it?
In some cases, you would like to use Jenkins declarative pipeline with the dynamic agent. For instance, you want to ...
Groovy Ecosystem Usage Report (2020)
What is the most popular Groovy library, framework, or a tool? I surveyed 308 Groovy community members, and here are...
How to convert JSON to CSV from the command-line?
Are you looking for an easy and fast way to convert a JSON file to a CSV one? In this blog post, I will show you how...
5 Common Jenkins Pipeline Mistakes
Do you know that you can unit test your Jenkins pipeline code? Have you ever used linter to validate the syntax of t...
How to merge two maps in Groovy?
One of the most popular map-related operation in any programming language is merging two (or more) maps. In this sho...
Building stackoverflow-cli with Java 11, Micronaut, Picocli, and GraalVM
In this blog post, I show you how to build stackoverflow-cli - a command-line application that allows you to search ...
How to catch curl response in Jenkins Pipeline?
In this blog post, I explain why you may want to use curl command in your Jenkinsfile, how to catch curl response an...
Atomic Habits - book review
Sticking to the process of achieving my goals has always been one of the most difficult obstacles to overcome, both ...
Parsing JSON in command-line with jq: basic filters and functions (part 1)
Have you ever wondered, what is the most convenient way to parse JSON data in the Unix/Linux command line? For insta...
How to time out Jenkins Pipeline stage and keep the pipeline running?
The declarative Jenkins Pipeline allows us to define timeout either at the pipeline level or the specific stage. Thi...
My first 200 YouTube subscribers - Thank You!
Many content creators celebrate their 10k, 100k, or 1M subscribers/followers milestones. There is nothing wrong with...
Groovy dynamic Maps, generic type erasure, and raw types - an interesting use case to learn from
Dynamic type inference in Groovy might be tricky. Add generic type erasure to it, and you can find yourself in troub...
Groovy 3 @NullCheck annotation - less code and less NPE
Groovy 3 helps you write less, but more secure code. Today I want to show you one of the features added in the lates...
Groovy 3 String GDK improvements - takeRight, takeBetween, and a few others
Groovy 3 was released a few days ago[1], and it introduced a lot of important new features to the language. Today I ...
Jenkins Scripted Pipeline vs. Declarative Pipeline - the 4 practical differences
If you read this blog post, there is a high chance you’re looking for information about practical differences ...
The blog development report - year 2019
2019 was a fantastic year for my blog. I didn’t manage to write articles every month, but it didn’t stop...
24 posts
2019
Three Groovy String methods that will make your life Groovier!
Groovy String API offers many useful methods to make working with strings much more pleasant. Today I would like to ...
Using Jenkins Pipeline parallel stages to build Maven project with different JDKs
In one of the latest blog posts, I have shown you how you can build a Docker image with Java and Maven installed wit...
Quicksort in Groovy - can it be as fast as implemented in Java?
I started reading "Cracking the Coding Interview, 6th Edition" book recently and it inspired me to experim...
Using CircleCI to deploy Hexo blog to GitHub Pages - how to set it up?
I was using Travis CI to execute 271 builds and deployments of this blog. Last Friday, I decided to experiment with ...
Building Java and Maven docker images using parallelized Jenkins Pipeline and SDKMAN!
In the last article, I have shown you how you can build a docker image for Jenkins Pipeline using SDKMAN! command-li...
Using SDKMAN! as a docker image for Jenkins Pipeline - a step by step guide
A few days ago, I was struggling with some Docker images I use in my Jenkins CI environment. I run some Jenkins Pipe...
Jenkins Pipeline Environment Variables - The Definitive Guide
Have you run into troubles when you started using Jenkins Environment Variables in your Jenkinsfile? In this blog po...
Groovy Trampoline Closure - a step into recursive closures
A few weeks ago an interesting question was asked on the StackOverflow. Someone experimented with a recursion in Gro...
GR8Conf EU 2019 Recap
It’s been a week since GR8Conf EU 2019 is over, so it is the right time to write some recap of this outstandin...
GR8Conf EU 2019 - what can you expect from my talks?
GR8Conf EU 2019 starts precisely in 13 days (on May 27th). Each year Copenhagen becomes a heart of Groovy vibrant co...
Debugging Teams - book review
"Geniuses still make mistakes and having brilliant ideas and elite programming skills don’t guarantee that you...
Spock random order of tests - how to?
Spock Framework executes test methods (features) in a single class (specification) in the declaration order. There i...
GraalVM and heap size of the native image - how to set it?
In this short blog post, I would like to show you how to set a heap size of the application executed from the native...
Using the same prefix with different HTTP methods in Ratpack
Ratpack is an excellent tool for building RESTful[1] applications. However, to benefit most of it, we need to know t...
Pragmatic Thinking and Learning - book review
There are books you read once, and you don’t plan to read them back again any time soon. However, some books a...
Installing GraalVM EE 1.0.0-RC14 with SDKMAN!
I love SDKMAN!. It made using multiple different Java distributions in a single operating system much more comfortab...
Groovy Regular Expressions - The Benchmark (Part 2)
In the second part of the "Groovy Regular Expression" blog post, I want to show you some benchmarks. And let me make...
Groovy Regular Expressions - The Definitive Guide (Part 1)
Welcome to "Groovy Regular Expressions - The Definitive Guide"! In the next 15 minutes, you are going to learn every...
IntelliJ IDEA and Git's "gpg failed to sign the data"
Today I’ve decided to improve my Github account settings a bit. I thought that it would be nice to add GPG key...
Release It! 2nd edition - book review
We are software developers. Our daily duty is to write programs. We spend a lot of time and effort into doing the ri...
How to remove any class annotation with Groovy compiler configuration script?
One of the most interesting Groovy features is its ability to configure advanced compiler[1] options using DSL scrip...
Ratpack on GraalVM - how to start?
The journey inside the exciting world of GraalVM continues. Today I would like to share with you results of running...
GraalVM native image inside docker container - does it make sense?
We have learned how to create GraalVM native image from standalone Groovy script in the previous blog post. Today we...
GraalVM with Groovy and Grape - creating native image of a standalone script
The Apache Groovy programming language has extraordinary scripting capabilities. When you combine it with the Grape ...
24 posts
2018
Deep Work - book review
This is the second blog post in "Programmer’s Bookshelf" category, and today I would like to share with you my...
Programming Groovy 2 - book review
When I get the paperback copy of the "Programming Groovy 2" book back in the June 2017, I was wondering if I can fin...
Spock assertion inside if-statement doesn't work - why?
Spock Framework is one of my favorite tools in the Groovy ecosystem toolbox. It makes writing automated tests a few ...
JUnit Assume.assumeNotNull(obj) throws NullPointerException in Groovy - what's wrong?
Ignoring some of the unit tests when given conditions are not satisfied is a handy feature of a JUnit framework. I g...
Don't waste your time - Advent Of Code 2018 is running!
The 4th edition of Advent Of Code just started! In this short blog post, I would like to share with you some of my t...
List of combinations from a list of lists in Groovy
Groovy has many useful functions built-in, and one of them is Iterable.combinations() that takes aggregated collecti...
Tail-recursive methods in Groovy
Most of the object-oriented programmers prefer constructing algorithms using imperative style over using recursion. ...
Non-blocking and async Micronaut - quick start (part 3)
Welcome to the part 3 of "Non-blocking and async Micronaut" article. In the previous post we have created connection...
Java 8 type inference in generic methods chain call - what might go wrong?
Yesterday I have found this interesting question on Stack Overflow asked by Opal. He faced some unexpected compilati...
Non-blocking and async Micronaut - quick start (part 2)
Welcome to the part 2 of "Non-blocking and async Micronaut" article. In the previous part we have explained the idea...
Non-blocking and async Micronaut - quick start (part 1)
Micronaut framework inventors says it is designed for building modern microservice applications. It supports reactiv...
How to avoid "No tests were found" when using JUnit 5 with Groovy?
In this short blog post I would like to explain how to avoid popular mistake when you write your first JUnit 5 test ...
GraalVM and Groovy - how to start?
GraalVM became one of the most popular topics in the JVM ecosystem. It promises the highest possible speed of runnin...
What is the most efficient way to iterate collection in Groovy? Let's play with JMH!
I guess you may heard about Groovy’s Collection.each(Closure cl) method - it was introduced 15 years ago [1] a...
Hexo git deployer removes commits history? Let's do something about that!
I have found Hexo a great tool for building a blog and apply many well-known software development principles. One of...
How Groovy's equal operator differs from Java?
One of the first mistakes people do when starting their journey with Java programming language is using == to compar...
Groovy: static propertyMissing and methodMissing methods - limitations and possible issues
Some time ago I have found another interesting Groovy related question on Stack Overflow. This time someone was aski...
Groovy: dynamic types coercion and promotion - you have been warned!
Groovy is a very powerful language on a JVM platform and with this great power comes great responsibility. There are...
365 consecutive days on Stack Overflow - what I have learned from this experiment
A few days ago I have reached 365 consecutive days on Stack Overflow. In the beginning of July 2017 I have deci...
How to name Groovy script file?
Some time ago I have found a very interesting question on Stack Overflow about forbidden characters in Groovy script...
Groovy: split string and avoid getting IndexOutOfBoundsException
If you use Groovy for scripting or other similar tasks you probably faced a situation where you get an input as a te...
Ratpack: register SessionModule in handler unit test
Unit testing Ratpack handlers has many benefits. In the previous post we have learned how to mock Session object to ...
Ratpack: mocking Session object in GroovyRequestFixture test
Ratpack allows you unit test handlers using GroovyRequestFixture class. The good thing about this approach is that i...
Count frequency of a digit in a factorial of number using Haskell
Some time ago I was interviewed to one of the Java-based projects and I was asked to solve this pretty interesting p...
3 posts
2017
Groovy script: closure does not modify @Field annotated variable
Recently I have answered a few questions on Stack Overflow related to Groovy scripts and how they work in combinatio...
Why "grails package" executes Config.groovy file?
This blog post is inspired by one of my recent Stack Overflow answers to following question: Grails: why is the Conf...
Divide a list to lists of n size in Java 8
Every Java developer works with lists daily. There are many popular list (or collection) operations implemented in t...