[Java RESTEasy client] updating test to use the Java RESTEasy echo api client (#17367) (#17470)

* updating test to use the Java RESTEasy echo api client (#17367)

* regenerated samples

* set source and target to 1.8 to fix workflow failure, adapted parser

samples/client/echo_api/java/feign-gson/api/openapi.yaml

@@ -513,6 +513,27 @@ paths:
       tags:
       - body
       x-accepts: image/gif
+  /body/application/octetstream/single_binary:
+    post:
+      description: Test single binary in multipart mime
+      operationId: test/body/multipart/formdata/single_binary
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              $ref: '#/components/schemas/test_body_multipart_formdata_single_binary_request'
+      responses:
+        "200":
+          content:
+            text/plain:
+              schema:
+                type: string
+          description: Successful operation
+      summary: Test single binary in multipart mime
+      tags:
+      - body
+      x-content-type: multipart/form-data
+      x-accepts: text/plain
   /body/application/octetstream/array_of_binary:
     post:
       description: Test array of binary in multipart mime
@@ -825,6 +846,12 @@ components:
       allOf:
       - $ref: '#/components/schemas/Bird'
       - $ref: '#/components/schemas/Category'
+    test_body_multipart_formdata_single_binary_request:
+      properties:
+        my-file:
+          format: binary
+          type: string
+      type: object
     test_body_multipart_formdata_array_of_binary_request:
       properties:
         files:

samples/client/echo_api/java/feign-gson/src/main/java/org/openapitools/client/api/BodyApi.java

@@ -101,6 +101,35 @@ public interface BodyApi extends ApiClient.Api {
 
 
 
+  /**
+   * Test single binary in multipart mime
+   * Test single binary in multipart mime
+   * @param myFile  (optional)
+   * @return String
+   */
+  @RequestLine("POST /body/application/octetstream/single_binary")
+  @Headers({
+    "Content-Type: multipart/form-data",
+    "Accept: text/plain",
+  })
+  String testBodyMultipartFormdataSingleBinary(@Param("my-file") File myFile);
+
+  /**
+   * Test single binary in multipart mime
+   * Similar to <code>testBodyMultipartFormdataSingleBinary</code> but it also returns the http response headers .
+   * Test single binary in multipart mime
+   * @param myFile  (optional)
+   * @return A ApiResponse that wraps the response boyd and the http headers.
+   */
+  @RequestLine("POST /body/application/octetstream/single_binary")
+  @Headers({
+    "Content-Type: multipart/form-data",
+    "Accept: text/plain",
+  })
+  ApiResponse<String> testBodyMultipartFormdataSingleBinaryWithHttpInfo(@Param("my-file") File myFile);
+
+
+
   /**
    * Test body parameter(s)
    * Test body parameter(s)