private boolean isRequiredAnnotation(MethodParameter parameter) {
		RequestParam requestParam = parameter.getParameterAnnotation(RequestParam.class);
		PathVariable pathVariable = parameter.getParameterAnnotation(PathVariable.class);
		org.springframework.web.bind.annotation.RequestBody requestBody = parameter.getParameterAnnotation(org.springframework.web.bind.annotation.RequestBody.class);
		return (requestParam != null && requestParam.required())
				|| (pathVariable != null && pathVariable.required())
				|| (requestBody != null && requestBody.required());
	}
Is required annotation boolean.

@param parameter the parameter
@return the boolean
springdoc-openapi-starter-common/src/main/java/org/springdoc/core/service/AbstractRequestService.java