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BlockHound: How it Works

One of the talks in my current portfolio is Migrating from Imperative to Reactive. The talk is based on a demo migrating from Spring WebMVC to Spring WebFlux in a step-by-step approach. One of the steps involves installing BlockHound: it allows to check whether a blocking call occurs in a thread it shouldn't happen and throws an exception at runtime when it happens.

I've presented this talk several times in the previous week, both in its Java version and its Kotlin one. One such presentation was at Javaday Istanbul. After the talk, one of the questions I received was, "How does BlockHound work?" I admit that at the time, I couldn't remember. After the surprise had passed, but too late, I remembered it involved a Java agent. But I wanted to go down the rabbit hole.

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Increase Throughput by Eliminating Blocking Code in Your Java REST App

Blocking code is code which blocks executing threads until their operations finish. It's not always bad to block a thread and wait until the result is ready but there are situations where it's not optimal from a throughput and memory point of view. This article assumes some basic knowledge about the differences between blocking and non-blocking code.

What I am going to do is to introduce a very simple app with some blocking code inside and show you how you can easily figure out where your threads are usually blocked and then you might identify a better way to implement those certain parts of code and do it much more efficiently.