[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/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)