How to Fix @RequestBody Compatibility and Swagger Timeout Issues in Spring Boot

@RequestBody Compatibility Issue

When adding Swagger to a Spring Boot project, the @requestBody annotation conflicts with Swagger's processing, because Spring MVC's default argument resolver and Swagger require opposite handling of @RequestBody. Two common work‑arounds are:

Separate production and test environments via configuration to avoid the conflict.

Modify the argument resolver priority so that a custom resolver outranks RequestResponseBodyMethodProcessor, allowing @RequestBody on custom parameters while keeping Swagger functional.

Both approaches add complexity and often require additional imports that may introduce version‑compatibility problems, so the author abandoned them.

Swagger API Timeout

The author experienced a severe slowdown when generating Swagger JSON with Swagger 3, taking about 30 seconds locally. Investigation on StackOverflow revealed that Groovy’s groovy.lang.MetaClass is included for every Groovy class, inflating the model size and causing the timeout.

One‑Click Fix

The effective solution, also found on StackOverflow, is to filter out groovy.lang.MetaClass in the Swagger configuration. Adding a simple bean that excludes this type shortens the JSON generation to a few seconds and, as a side effect, also resolves the @requestBody compatibility problem.

@Bean
public Docket api() {
    return new Docket(DocumentationType.SWAGGER_2)
        .select()
        .apis(RequestHandlerSelectors.any())
        .build()
        .ignoredParameterTypes(groovy.lang.MetaClass.class);
}