java-runtime-(de)compiler

Speaker: Jiří Vaněk (jvanek@redhat.com, Red Hat)

Abstract:

Java runtime decompiler is a tool that can connect to a running VM, obtain bytecode, decompile it, change it, and compile it back. As hotspot class redefinition and decompilers have their limits, they also use bytecode assembly language and byteman to inspect and modify running VMs. For the sake of completeness, it has simple asm/byteman code-completion, diff, and patchwork and is also able to work transparently on the local filesystem.

In this talk, I will cover the differences between individual runtime modification approaches and the hotswap limitation. I will share a lesson learned from (mis)using Instrumentation and ClassFileTransformer APIs. There will also be a demo to show that all in action.

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After the talk, we will have the afterparty as usual. Come to learn about bytecode transformation magic and have great technical discussions afterward!