Spring Java Codegen test generation incorrect

Description

Unit test code output for functions involving Java Map objects does not generate a valid stub since it tries to instantiate the "Map" interface instead of a concrete class (like HashMap)

Swagger-codegen version

3.0.10

Code output

(snippet of test)

    @Test
    public void queryTest() throws Exception {
        Map<String, Object> body = new Map();
        ResponseEntity<Message> responseEntity = api.query(body);
        assertEquals(HttpStatus.NOT_IMPLEMENTED, responseEntity.getStatusCode());
    }

Swagger declaration file content or url

Reproduce the generated Spring Java test with the supplied OpenAPI YAML, then inspect the Spring Java code-generation templates or entry points responsible for request-body test stubs. Done means Map-based inputs generate a valid concrete implementation rather than instantiating the Map interface, and the generated test compiles.