Getting familiar with complicated technical topics like concurrency or recursion, we often look to abstractions. We boil things down to diagrams with boxes and arrows, tucking the details away for later.

While often a great starting point, there’s a lot of value in pushing the other direction too. On the JVM, reality isn’t your Java, Kotlin, or Clojure code -- it’s the bytecode running below the surface. Surprisingly, many elusive topics may actually be clearer when we can understand what’s happening at that layer below.

In this talk, we’ll get up to speed on just enough bytecode reading to start exploring real topics like lost writes from concurrency, tail recursion, and co-routines. We’ll get familiar with the basic tools and opcodes, what to do when the bytecode’s hard to understand, and come away more confident in our ability to understand our systems from top to bottom.