generate error api for rest template spring

I have api:

{
    "swagger": "2.0",
    "info": {
        "description": "",
        "version": "1.0.0",
        "title": "v2",
        "contact": {
            "name": "Aleksey2093",
            "email": ""
        },
        "license": {
            "name": "Apache 2.0",
            "url": "http://www.apache.org/licenses/LICENSE-2.0"
        }
    },
    "host": "localhost:8080",
    "basePath": "/api",
    "tags": [
        {
            "name": "files-controller",
            "description": "Files Controller"
        }
    ],
    "paths": {
        "/files/info-files": {
            "post": {
                "tags": [
                    "files-controller"
                ],
                "summary": "create or update",
                "operationId": "createInfoFileUsingPOST",
                "consumes": [
                    "multipart/form-data"
                ],
                "produces": [
                    "application/json"
                ],
                "parameters": [
                    {
                        "in": "formData",
                        "name": "comment",
                        "description": "comment",
                        "required": false,
                        "schema": {
                            "type": "string"
                        }
                    },
                    {
                        "name": "file",
                        "in": "formData",
                        "description": "file",
                        "required": false,
                        "type": "file"
                    },
                    {
                        "in": "formData",
                        "name": "icon",
                        "description": "icon",
                        "required": true,
                        "schema": {
                            "type": "string"
                        }
                    },
                    {
                        "in": "formData",
                        "name": "isVisible",
                        "description": "isVisible",
                        "required": true,
                        "schema": {
                            "type": "boolean"
                        }
                    },
                    {
                        "in": "formData",
                        "name": "uri",
                        "description": "uri remote",
                        "required": false,
                        "schema": {
                            "type": "string"
                        }
                    }
                ],
                "responses": {
                    "201": {
                        "description": "good",
                        "schema": {
                            "originalRef": "PayloadResponse",
                            "$ref": "#/definitions/PayloadResponse"
                        }
                    },
                    "400": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "403": {
                        "description": "Need Auth",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "404": {
                        "description": "Not found",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "422": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "500": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    }
                },
                "responsesObject": {
                    "201": {
                        "description": "Good",
                        "schema": {
                            "originalRef": "PayloadResponse",
                            "$ref": "#/definitions/PayloadResponse"
                        }
                    },
                    "400": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "403": {
                        "description": "Need Auth",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "404": {
                        "description": "Not found",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "422": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    },
                    "500": {
                        "description": "Error",
                        "schema": {
                            "originalRef": "ErrorBody",
                            "$ref": "#/definitions/ErrorBody"
                        }
                    }
                },
                "deprecated": false
            }
        }
    },
    "definitions": {
        "ErrorBody": {
            "type": "object",
            "required": [
                "message"
            ],
            "properties": {
                "description": {
                    "type": "string",
                    "description": "developer"
                },
                "errors": {
                    "type": "array",
                    "description": "Errors",
                    "items": {
                        "originalRef": "ErrorItem",
                        "$ref": "#/definitions/ErrorItem"
                    }
                },
                "message": {
                    "type": "string",
                    "description": "message for user"
                }
            },
            "title": "ErrorBody",
            "description": "ErrorBody"
        },
        "ErrorItem": {
            "type": "object",
            "required": [
                "message"
            ],
            "properties": {
                "description": {
                    "type": "string",
                    "description": "developer"
                },
                "field": {
                    "type": "string",
                    "description": "field name from request"
                },
                "message": {
                    "type": "string",
                    "description": "message for user"
                }
            },
            "title": "ErrorItem",
            "description": "Error"
        },
        "InputStream": {
            "type": "object",
            "title": "InputStream"
        },
        "PayloadResponse": {
            "type": "object",
            "required": [
                "message",
                "success"
            ],
            "properties": {
                "payload": {
                    "type": "object",
                    "description": "data"
                },
                "success": {
                    "type": "boolean",
                    "description": "success?"
                },
                "message": {
                    "type": "string",
                    "description": "message for user"
                }
            },
            "title": "PayloadResponse",
            "description": "response"
        }
    }
}

generate project for api:

java -DmodelTests=false -DapiTests=false -jar ./swagger-codegen-cli-3.0.35.jar generate \
        -i ./api-docs.json \
        -l java \
        --library resttemplate \
        --invoker-package aleksey2093.back.end.v2.api.invoker \
        --model-package aleksey2093.back.end.v2.api.model \
        --api-package aleksey2093.back.end.v2.api.controller \
        --group-id aleksey2093 \
        --artifact-id test \
        --artifact-version test \
        -o target/gen-swagger-api --additional-properties dateLibrary=java8-localdatetime,java8=true

generate error code:

public ResponseEntity<PayloadResponse> createInfoFileUsingPOSTWithHttpInfo(Object comment, File file, Object icon, Object isVisible, Object uri) throws RestClientException {
        Object postBody = null;
        // verify the required parameter 'comment' is set
        if (comment == null) {
            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'comment' when calling createInfoFileUsingPOST");
        }
        // verify the required parameter 'file' is set
        if (file == null) {
            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'file' when calling createInfoFileUsingPOST");
        }
        // verify the required parameter 'icon' is set
        if (icon == null) {
            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'icon' when calling createInfoFileUsingPOST");
        }
        // verify the required parameter 'isVisible' is set
        if (isVisible == null) {
            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'isVisible' when calling createInfoFileUsingPOST");
        }
        // verify the required parameter 'uri' is set
        if (uri == null) {
            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'uri' when calling createInfoFileUsingPOST");
        }
        String path = UriComponentsBuilder.fromPath("/files/info-files").build().toUriString();

but comment, file and uri are not required fields.

Start by running the shown swagger-codegen-cli command with api-docs.json and compare its generated createInfoFileUsingPOSTWithHttpInfo method with the parameter required flags in the specification. Trace the Java RestTemplate generation entry point and related template, then verify that only parameters marked required are validated as required in the generated code.