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JVM Method Descriptor Parameter and Local-Variable Slot Layout Reconstructor
x402
JVM Method Descriptor Parameter and Local-Variable Slot Layout Reconstructor is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-04).
Parses a JVM method descriptor string and returns the full parameter breakdown, return type, and initial local-variable slot assignments for use in classfile emission.
Price / call$0.003
Success—
StatusUnknown
How this service works
Reconstruct JVM parameter and return descriptors and initial local-variable slots for a classfile emitter.
Output
Returns a structured claim object containing: an array of parameters each with descriptor string, resolved type name, array dimensions, slot count (1 or 2), and local_slot index; a return_type object with the same fields minus local_slot; total parameter_slots count; and initial_local_slots count (accounting for implicit 'this' on instance methods).
Example use cases
Classfile emitter local slot setup
“I'm building a JVM classfile emitter and I have the method descriptor '(Ljava/lang/Object;IJ)Z' for a static method — can you reconstruct the parameter types, their slot assignments, and tell me the total initial local slots needed?”
Bytecode rewriter parameter layout check
“I need to rewrite a non-static JVM method with descriptor '(DDLjava/lang/String;)Ljava/lang/Object;' — parse it and give me each parameter's type, descriptor, array dimensions, slot size, and local slot index so I can correctly offset my bytecode.”
Compiler backend descriptor validation
“My compiler backend is generating a static method with descriptor '([ILjava/util/List;B)V' — validate the descriptor, extract all parameter descriptors and types, and return how many local variable slots the method starts with.”
Technical details
Endpoint
POSThttps://detect.halowerk.com/v1/F-TD2000-DOCUMENTS-06/jvms25-method-descriptor-parameter-local-slot-layout?utm_source=zero.xyzWhen to prefer
Use this endpoint when building JVM bytecode emitters, compilers, or bytecode rewriters that need to programmatically determine local variable slot layout from a raw method descriptor string. It is especially useful when you need the exact local_slot index for each parameter (accounting for long/double double-slot types and the implicit 'this' reference in instance methods) without implementing the JVM spec parsing logic yourself.
Side effects
- Malformed or syntactically invalid JVM descriptor string returns an error
- Descriptor exceeding 1024 characters is rejected by schema validation
- Missing required fields (descriptor or is_static) causes a 400-level error
- Descriptors with more than 255 parameters may be rejected
- Network or service unavailability returns a non-200 response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| artifact | object |
Tags
x402
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