The Java Class File API
summary
Many third party libraries like ASM BCEL and Javassist exist but Java 24 now provides a standard Class File API since Java 24 that parses and builds class files via immutable class models and replayable builders. Examples show dumping constant-pool strings, inserting a logging call at method entry via the transformations helpers, and adding automatic memoization of recursive methods by rewriting a method into a cached impl plus wrapper. Demos use the instrumentation agent for load‑time rewriting and speed fib(60) from unusable to instant.
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chapters (9)
- 0:00Java class file API intro
- 4:59Why use the API
- 9:16Bytecode basics
- 15:18Building a class file
- 22:09Adding logging calls
- 30:17Runtime transformation with agents
- 33:04Bytecode memoization
- 47:18Immutable trees usability
- 48:43Q&A
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