Jim Callback
A script callback, normalized so the engine can invoke it the same way regardless of which engine produced it:
HandleCallback wraps a JVM callable — a bytecode-path arrow/named function swc4j compiled to a
java.util.function.*lambda, or a GraalJS guest function that GraalJS coerced into such a SAM when it was passed to aConsumer/Runnable-typed API method (e.g. ratph6.jim.api.Jim.register).GraalCallback wraps a raw GraalJS guest function (e.g. a module's exported function looked up by name from its namespace) and calls it directly.