[BUG] [Java Native] client incorrect generation of `application/octet-stream`

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• [x]Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

When generating a native Java client using application/octet-stream it incorrectly tries to decode it to JSON using ObjectMapper.

openapi-generator version

7.2.0

OpenAPI declaration file content or url

"/datasetrw/snapshot/{snapshotId}/file/raw": {
      "get": {
        "operationId": "getFileRaw",
        "parameters": [
          {
            "description": "snapshot ID",
            "in": "path",
            "name": "snapshotId",
            "required": true,
            "schema": {
              "pattern": "^[0-9a-f]{24}$",
              "type": "string"
            }
          },
          {
            "description": "path of file to get raw content for",
            "in": "query",
            "name": "path",
            "required": true,
            "schema": {
              "type": "string"
            }
          },
          {
            "description": "whether endpoint is used for download",
            "in": "query",
            "name": "download",
            "required": false,
            "schema": {
              "nullable": true,
              "type": "boolean"
            }
          }
        ],
        "responses": {
          "200": {
            "content": {
              "application/octet-stream": {
                "schema": {
                  "format": "binary",
                  "type": "string"
                }
              }
            },
            "description": "success"
          },
          "400": {
            "$ref": "#/components/responses/BadRequest"
          },
          "401": {
            "$ref": "#/components/responses/Unauthorized"
          },
          "403": {
            "$ref": "#/components/responses/Forbidden"
          },
          "500": {
            "$ref": "#/components/responses/InternalError"
          }
        },
        "summary": "Get snapshot file raw content at specified path",
        "tags": [
          "DatasetRw"
        ]
      }
    },

Generation Details

It then generates this Java code trying to convert it to java.io.File...

public ApiResponse<File> getFileRawWithHttpInfo(String snapshotId, String path, Boolean download) throws ApiException {
    HttpRequest.Builder localVarRequestBuilder = getFileRawRequestBuilder(snapshotId, path, download);
    try {
      HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
          localVarRequestBuilder.build(),
          HttpResponse.BodyHandlers.ofInputStream());
      if (memberVarResponseInterceptor != null) {
        memberVarResponseInterceptor.accept(localVarResponse);
      }
      try {
        if (localVarResponse.statusCode()/ 100 != 2) {
          throw getApiException("getFileRaw", localVarResponse);
        }
        return new ApiResponse<File>(
          localVarResponse.statusCode(),
          localVarResponse.headers().map(),
          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<File>() {}) // closes the InputStream
        );
      } finally {
      }
    } catch (IOException e) {
      throw new ApiException(e);
    }
    catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      throw new ApiException(e);
    }
  }

You can see this line is incorrect.

  localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<File>() {}) // closes the InputStream

Its using the JSON Mapper to try and convert to a File.

Use the provided OpenAPI declaration to reproduce native Java client generation, then inspect the generated getFileRawWithHttpInfo method and trace the Java Native response-generation path that produces it. Done means an application/octet-stream response is handled as binary data rather than passed to ObjectMapper for File conversion, with the generated output demonstrating the corrected behavior.