Tag Archives: Kotlin

The object keyword in Kotlin creates singleton in a very convenient way. It can be used for example as a state of an operation. Spock Framework is one of the most expressive and readable test framework available in the Java ecosystem. Let’s see how Kotlin object can be used in the Spock tests. What do we want to test? We ...

This post is the second part of a 3 post series exploring ways to enable SSO with an OAuth2 provider for Spring Boot 2 based applications. The 3 posts are: 1.Ways to bootstrap an OpenID Connect compliant OAuth2 Authorization Server/OpenID Provider 2. Legacy Spring Boot/Spring 5 approach to integrating with an OAuth2 Authorization Server/OpenID Provider – this post 3. Newer ...

This is a quick write-up on migrating a Gradle based Spring Boot app from Junit 4 to the shiny new Junit 5. Junit 4 tests continue to work with Junit 5 Test Engine abstraction which provides support for tests written in different programming models, in this instance, Junit 5 supports a Vintage Test Engine with the ability to run JUnit 4 ...

Kotlin compiler optimizes tail recursive calls with a few catches. Consider a rank function to search for the index of an element in a sorted array, implemented the following way using tail recursion and a test for it: fun rank(k: Int, arr: Array<Int>): Int { tailrec fun rank(low: Int, high: Int): Int { if (low > high) { return -1 } ...

Spring Webflux and Spring Web are two entirely different web stacks. Spring Webflux, however, continues to support an annotation-based programming model An endpoint defined using these two stacks may look similar but the way to test such an endpoint is fairly different and a user writing such an endpoint has to be aware of which stack is active and formulate the test accordingly. Sample Endpoint ...

Introduction Man, I’ve had this idea in my head for more than a month now (luckily I wrote it down, too), waiting until the day I wrote this post. I didn’t write it because I was busy with the move and new job, but now things are finally settling down! Here’s the thing: When you really dig into it, proper ...

I saw an exercise in chapter 3 of the excellent Functional Programming in Scala book which deals with defining functional data structures and uses the linked list as an example on how to go about developing such a datastructure. I wanted to try this sample using Kotlin to see to what extent I can replicate the sample. A scala skeleton of ...

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In a previous blog post I had described how Spring Webflux, the reactive programming support in Spring Web Framework, uses a Kotlin based DSL to enable users to describe routes in a very intuitive way. Here I wanted to explore a little of the underlying implementation. A sample DSL describing a set of endpoints looks like this: package sample.routes import org.springframework.context.annotation.Bean ...