What's in a Good Error Message?
Update Jan 13: This post is discussed on Reddit
As software developers, we’ve all come across those annoying, not-so-useful error messages when using some library or framework: "Couldn’t parse config file", "Lacking permission for this operation", etc. Ok, ok, so something went wrong apparently; but what exactly? What config file? Which permissions? And what should you do about it? Error messages lacking this kind of information quickly create a feeling of frustration and helplessness.
So what makes a good error message then? To me, it boils down to three pieces of information which should be conveyed by an error message:
Context: What led to the error? What was the code trying to do when it failed?
The error itself: What exactly failed?
Mitigation: What needs to be done in order to overcome the error?
Announcing the First Release of kcctl
🧸 It’s Casey. Casey Cuddle.
I am very happy to announce the first stable release of kcctl, a modern and intuitive command line client for Apache Kafka Connect!
Forget about having to memorize and type the right REST API paths and curl flags; with kcctl, managing your Kafka connectors is done via concise and logically structured commands, modeled after the semantics of the kubectl tool known from Kubernetes.
Introducing the OSS Quickstart Archetype
I am very happy to announce the availability of the OSS Quickstart Archetype!
Part of the ModiTect family of open-source projects, this is a Maven archetype which makes it very easy to bootstrap new Maven-based open-source projects, satisfying common requirements such as configuring plug-in versions, and adhering to best practices like auto-formatting the source code. Think Maven Quickstart Archetype and friends, but more modern, complete, and opinionated.
O Kafka, Where Art Thou?
The other day, I came across an interesting thread in the Java sub-reddit, with someone asking: "Has anyone attempted to write logs directly to Kafka?". This triggered a number of thoughts and questions for myself, in particular how one should deal in an application when an attempt to send messages to Kafka fails, for instance due to some network connectivity issue? What do you do when you cannot reach the Kafka broker?
Refining The Return Type Of Java Methods Without Breaking Backwards-Compatibility
If you work on any kind of software library, ensuring backwards-compatibility is a key concern: if there’s one thing which users really dislike, it is breaking changes in a new version of a library. The rules of what can (and cannot) be changed in a Java API without breaking existing consumers are well defined in the Java language specification (JLS), but things can get pretty interesting in certain corner cases.
The Eclipse team provides a comprehensive overview about API evolution guidelines in their wiki. When I shared the link to this great resource on Twitter the other day, I received an interesting reply from Lukas Eder:
I wish Java had a few tools to prevent some cases of binary compatibility breakages. E.g. when refining a method return type, I’d like to keep the old method around in byte code (but not in source code). I think kotlin has such tools? In the remainder of this post, I’d like to provide some more insight into that problem mentioned by Lukas, and how it can be addressed using an open-source tool called Bridger.
JDK Flight Recorder Events in GraalVM Native Binaries
If you have followed this blog for a while, you’ll know that I am a big fan of JDK Flight Recorder (JFR), the low-overhead diagnostics and profiling framework built into the HotSpot Java virtual machine. And indeed, until recently, this meant only HotSpot: Folks compiling their Java applications into GraalVM native binaries could not benefit from all the JFR goodness so far.
Debezium and Friends – Conference Talks 2021
If you love to attend conferences around the world without actually leaving the comfort of your house, 2021 certainly was (and is!) a perfect year for you. Tons of online conferences, many of them available for free, are hosting talks on all kinds of topics, and virtual conference platforms are getting better, too.
As the year is slowly reaching its end, I thought it might be nice to do a quick recap and gather in one place all the talks on Debezium and change data capture (CDC) which I did in 2021.
What's on My Desk?
I’ve been working from home exclusively for the last nine years, but it was only last year that I started to look into ways for expanding my computer set-up and go beyond the usual combination of having a laptop with your regular external screen. The global COVID-19 pandemic, the prospect of having more calls with colleagues than ever (no physical meetings), and the constantly increasing need for recording talks for online conferences and meet-ups made me reevaluate things and steadily improve and fine tune my set-up, in particular in regards to better video and audio quality.
Executable JavaDoc Code Snippets
It has been just a few weeks since the release of Java 17, but the first changes scheduled for Java 18 begin to show up in early access builds. One feature in particular that excites me as a maintainer of different Java libraries is JEP 413 ("Code Snippets in Java API Documentation").
Resource Bundle Look-ups in Modular Java Applications
The ResourceBundle class is Java’s workhorse for managing and retrieving locale specific resources, such as error messages of internationalized applications. With the advent of the module system in Java 9, specifics around discovering and loading resource bundles have changed quite a bit, in particular when it comes to retrieving resource bundles across the boundaries of named modules.
In this blog post I’d like to discuss how resource bundles can be used in a multi-module application (i.e. a "modular monolith") for internationalizing error messages. The following requirements should be satisified: