Class-file parsing with the standard API
Use the standard Class-File API for class-file parsing and transformation.
Code Comparison
✕ Third-party bytecode parser
ClassReader reader = new ClassReader(
Files.readAllBytes(classFile));
reader.accept(visitor, 0);
✓ Java 24+
ClassModel model = ClassFile.of().parse(classFile);
model.methods().forEach(method ->
System.out.println(
method.methodName().stringValue()));
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Why the modern way wins
Supported API
Ships and evolves with the JDK class-file format.
Fewer dependencies
Handles common bytecode tasks without an external library.
Composable models
Parsing, building, and transformation share one API.
Old Approach
ASM ClassReader
Modern Approach
Class-File API
Since JDK
24
Difficulty
Advanced
JDK Support
Class-file parsing with the standard API
Available
Finalized in JDK 24 (JEP 484, March 2025).
How it works
The Class-File API, finalized in JDK 24, provides supported models and transformations for JVM class files. It tracks the class-file format with the JDK and removes the need for third-party libraries in many inspection and generation tasks.
Related Documentation
Proof