Invalid java client code is generated when body parameter is a map.

Description

When body parameter is a map, generated code is not correct.
Currently "Object" is generated. It should have been Map<String, Object>

Swagger-codegen version 2.2.3

Swagger declaration file content or url

{
            "in": "body",
            "name": "body",
            "description": "description",
            "required": true,
            "schema": {
              "type": "object",
              "additionalProperties": {
                "type": "object"
              }
            }
          }

Command line used for generation

generate -i swagger.json -l java -o output

Suggest a fix/enhancement

Generated Code:

 public ApiResponse<RefLinkDto> methodName( Object body) throws ApiException {
   
    }

Correct Code: 

 public ApiResponse<RefLinkDto> methodName(Map<String, Object> body) throws ApiException {
   
    }

Start by reproducing the issue with the generate command, the supplied Swagger body-parameter schema, and the Java target. Trace how Java client method parameters are selected for object schemas with additionalProperties; done means the generated method uses Map<String, Object> instead of Object for this input.