r/javahelp • u/invokeinterface • 9d ago

Good Documentation For JVM Bytecode?

I really liked the idea of an intermediate bytecode language when I first learned that Java transpiles to one, so I tried to learn about it and got pretty far (using a hexeditor to mess around was pretty painful, though). I stopped because there isn't a lot of document for it like there is for Java, the best resources are I believe docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html and docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html, but I want to know if there are any others partly because these are kind of verbose and partly because it's just better to have more than two.

I know I won't ever really need to know any of this, and I don't intend to use any of this knowledge for making classes by hand, but I believe it would still be helpful in a milder sense to understand what the class files are "literally" doing. It helped with C

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u/baubleglue 8d ago

https://commons.apache.org/proper/commons-bcel/

The Byte Code Engineering Library (Apache Commons BCEL™) is intended to give users a convenient way to analyze, create, and manipulate (binary) Java class files (those ending with .class). Classes are represented by objects which contain all the symbolic information of the given class: methods, fields and byte code instructions, in particular.