A Java geek

A SonarQube plugin for Kotlin - Analyzing with ANTLR

Last week, we used ANTLR to generate a library to be able to analyze Kotlin code. It’s time to use the generated API to check for specific patterns. API overview Let’s start by having a look at the generated API: KotlinLexer: Executes lexical analysis.KotlinParser: Wraps classes representing all Kotlin tokens, and handles parsing errors.KotlinParserVisitor: Contract for implementing the Visitor pattern on Kotlin code.

Technical

A SonarQube plugin for Kotlin - Paving the way

Since I started my journey into Kotlin, I wanted to use the same libraries and tools I use in Java. For libraries - Spring Boot, Mockito, etc., it’s straightforward as Kotlin is 100% interoperable with Java. For tools, well, it depends. For example, Jenkins works flawlessly, while SonarQube lacks a dedicated plugin. The SonarSource team has limited resources: Kotlin, though on the rise - and even more so since Google I/O 17, is not in their pipe.

Miscellaneous

It depends

In the industry, there’s this widespread joke. Whatever the question you ask a consultant, the answer will be: It depends. This joke is meant to highlight that consultants never give a straight answer to a simple question, because they don’t want to take any responsibility. While I understand the frustration of the business when faced with this situation, I’d like to write about the other side of the fence.

Java

What archive format should you use, WAR or JAR?

Some time ago, RAM and disk space were scarce resources. At that time, the widespread strategy was to host different applications onto the same platform. That was the golden age of the application server. I wrote in an earlier post that the current tendency toward cheaper resources will make it obsolete, in the short or long term. However, a technology trend might bring it back in favor.

Java

Why are you testing your software?

15 years ago, automated tests didn’t exist in the Java ecosystem. One had to build the application and painfully test it manually by using it. I was later introduced to the practice of adding a main method to every class and putting some testing code there. That was only marginally better, as it still required to manually run the methods. Then came JUnit, the reference unit testing framework in Java which brought test execution automation.

Java

Concurrency: Java Futures and Kotlin Coroutines

A long time ago, one had to manually start new threads when wanting to run code concurrently in Java. Not only was this hard to write, it was easy to introduce bugs that were hard to find. Testing, reading and maintaining such code was no walk in the park either. Since that time - and with a little incentive coming from multi-core machines, the Java API has evolved to make developing concurrent code easier.

Java

Java Service Loader vs Spring Factories Loader

Inversion of Control is not only possible at the class level, but at the module level. OSGi has been doing it for a long time. However, there are IoC approaches directly available in Java, as well as in Spring. Out-of-the-box, the Java API offers a specific form of Inversion of Control. It’s implemented by the Service Loader class.

Java

Fixing my own Spring Boot starter demo

Since one year or so, I try to show the developer community that there’s no magic involved in Spring Boot but rather just straightforward software engineering. This is achieved with blog posts and conference talks. At jDays, Stéphane Nicoll was nice enough to attend my talk and pointed out an issue in the code. I didn’t fix it then, and it came back to bite me last week during a Pivotal webinar.

Java

Custom collectors in Java 8

Among the many features available in Java 8, streams seem to be one of the biggest game changers regarding the way to write Java code. Usage is quite straightforward: the stream is created from a collection (or from a static method of an utility class), it’s processed using one or many of the available stream methods, and the collected back into a collection or an object. One generally uses one of the static method that the Collectors utility class offers: Collectors.toList()Collectors.

Nicolas Fränkel's blog