better java resteasy echo api client tests (#17473)

samples/client/echo_api/java/resteasy/docs/HeaderApi.md

@@ -0,0 +1,83 @@
+# HeaderApi
+
+All URIs are relative to *http://localhost:3000*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**testHeaderIntegerBooleanStringEnums**](HeaderApi.md#testHeaderIntegerBooleanStringEnums) | **GET** /header/integer/boolean/string/enums | Test header parameter(s) |
+
+
+
+## testHeaderIntegerBooleanStringEnums
+
+> String testHeaderIntegerBooleanStringEnums(integerHeader, booleanHeader, stringHeader, enumNonrefStringHeader, enumRefStringHeader)
+
+Test header parameter(s)
+
+Test header parameter(s)
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.HeaderApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost:3000");
+
+        HeaderApi apiInstance = new HeaderApi(defaultClient);
+        Integer integerHeader = 56; // Integer | 
+        Boolean booleanHeader = true; // Boolean | 
+        String stringHeader = "stringHeader_example"; // String | 
+        String enumNonrefStringHeader = "success"; // String | 
+        StringEnumRef enumRefStringHeader = StringEnumRef.fromValue("success"); // StringEnumRef | 
+        try {
+            String result = apiInstance.testHeaderIntegerBooleanStringEnums(integerHeader, booleanHeader, stringHeader, enumNonrefStringHeader, enumRefStringHeader);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling HeaderApi#testHeaderIntegerBooleanStringEnums");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **integerHeader** | **Integer**|  | [optional] |
+| **booleanHeader** | **Boolean**|  | [optional] |
+| **stringHeader** | **String**|  | [optional] |
+| **enumNonrefStringHeader** | **String**|  | [optional] [enum: success, failure, unclassified] |
+| **enumRefStringHeader** | [**StringEnumRef**](.md)|  | [optional] [enum: success, failure, unclassified] |
+
+### Return type
+
+**String**
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: text/plain
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | Successful operation |  -  |
+