Actually, never mind the reflection part, since you are using the annotation processor API, you need the latter option (generate Java compatible parameter names).

Ok so I've been playing with this and I'm still not seeing actual parameter names. This is my kotlin compiler configuration: <plugin> <artifactId>kotlin-maven-plugin</artifactId> <groupId>org.jetbrains.kotlin</groupId> <version>${kotlin.version}</version> <configuration> <javaParameters>true</javaParameters> </configuration> <executions> <execution> <id>compile</id> <phase>process-sources</phase> <goals> <goal>compile</goal> </goals> </execution> <execution> <id>test-compile</id> <phase>process-test-sources</phase> <goals> <goal>test-compile</goal> </goals> </execution> </executions> </plugin>

Is there something special I need to do within the annotation processing code to fetch the original name?

it's coming back as arg0

(etc)

I mean, I wrote up a method that will give a "sane default" based on the @RequestHeader.value and @RequestParam.value fields, but that's not ideal

Running the debugger I see there's a savedParameterNames List on the method that does contain the necessary info, but it's only available if I either cast the ExecutableElement to a Symbol.methodSymbol or dig into it using reflection. Where it's not available is on VariableElement.getSimpleName(). Playing around I did figure out I could directly assign one to the other in the debugger code evaluator but it's pretty ugly

Here's what I ended up doing - Tracking down in the debugger, I figured out I could just change the name field to the saved parameter names. It's a little ugly, but I'm running in a separate compile phase so no side effects to worry about private void attemptToReflectivelyRecoverMethodParameterNamesIfNeeded(ExecutableElement method) { try { List<String> savedParameterNames = (List<String>) method.getClass().getDeclaredField("savedParameterNames").get(method); //No savedParameters if (CollectionUtils.isEmpty(savedParameterNames)) { return; } List<? extends VariableElement> params = method.getParameters(); IntStream.range(0, params.size()).forEach(idx -> { VariableElement param = params.get(idx); if(param.getSimpleName().toString().matches("arg[0-9]+")) { try { param.getClass().getField("name").set(param, savedParameterNames.get(idx)); } catch (Exception e) { throw new RuntimeException("Exception setting param", e); } } }); } catch (Exception e) { processingEnv.getMessager().printMessage(Kind.WARNING, Util.getFormattedStackTrace(e)); } }