OW2 ASM and JEP 457: Class-File API

on YouTube ↗44m

" summary

Introduces the new JEP 457 Class-File API proposed as a preview in JDK 22 and compares it with the existing OW2 ASM library for low-level manipulation of compiled Java classes. Shows concrete use cases—creating classes for frameworks like Spring and Hibernate—and gives examples of static analysis on Java and Kotlin using OW2 ASM and the new Class-File API.

AI-written summary · about

" chapters (9)

1. 0:00Introduction
2. 2:51Why ASM library
3. 10:18Creating classes on the fly
4. 21:56Analyzing existing classes
5. 27:42ASM and JEP 457 problems
6. 29:06What is Class-File API
7. 32:16Code analysis example
8. 36:43ASM versus Class-File API
9. 37:47Summary

" related talks

• 52mA Classfile API for the JDKBrian Goetz · JVM Language Summit 2023
• 51mThe Java Class File APICay Horstmann · Jfokus 2026
• 32mUnveiling the Hidden Layers of Java Class Files Beyond BytecodeKoichi Sakata · Devnexus 2025
• 52mJava 22 and Beyond: A Roadmap of InnovationsAna-Maria Mihalceanu · Voxxed Days Brussels 2024
• 45mDeep Dive into the .class File and the Class LoaderKrzysztof Chruściel · JDD 2019
• 51mJava 24 - Better Language, Better APIs, Better RuntimeNicolai Parlog · Jfokus 2025
• 41mUsing Byte Code Analysis to Modernize Your Java EE ApplicationsCindy High · Devnexus 2022
• 45mMaking Java more dynamicRafael Winterhalter · JavaDay Lviv 2016