App Config - Head Requests by mrm9084 · Pull Request #48899 · Azure/azure-sdk-for-java

mrm9084 · 2026-04-22T19:18:40Z

Description

Adds head request support to the Java SDK.

See Python: Azure/azure-sdk-for-python#45858
See JS: Azure/azure-sdk-for-js#36959

All SDK Contribution checklist:

The pull request does not introduce [breaking changes]
CHANGELOG is updated for new features, bug fixes or other significant changes.
I have read the contribution guidelines.

General Guidelines and Best Practices

Title of the pull request is clear and informative.
There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

Pull request includes test coverage for the included changes.

Copilot

Pull request overview

This PR adds HEAD-request support to the Azure App Configuration Java SDK to enable efficient change detection via page-level ETags, without downloading response bodies.

Changes:

Added checkConfigurationSettings APIs to both sync (ConfigurationClient) and async (ConfigurationAsyncClient) clients, backed by the service’s HEAD /kv endpoint.
Added unit tests covering HEAD paging behavior (empty items, page ETag presence) and ETag change detection.
Added a new sample demonstrating polling-style change detection with cached page ETags, and updated the changelog.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
sdk/appconfiguration/azure-data-appconfiguration/src/main/java/com/azure/data/appconfiguration/ConfigurationClient.java	Adds sync `checkConfigurationSettings` API and JavaDoc samples.
sdk/appconfiguration/azure-data-appconfiguration/src/main/java/com/azure/data/appconfiguration/ConfigurationAsyncClient.java	Adds async `checkConfigurationSettings` API and JavaDoc samples.
sdk/appconfiguration/azure-data-appconfiguration/src/main/java/com/azure/data/appconfiguration/implementation/Utility.java	Adds helpers to translate HEAD responses into `PagedResponse` and handle 304 for HEAD, plus continuation parsing.
sdk/appconfiguration/azure-data-appconfiguration/src/test/java/com/azure/data/appconfiguration/ConfigurationClientTest.java	Adds sync tests for HEAD paging and ETag change detection.
sdk/appconfiguration/azure-data-appconfiguration/src/test/java/com/azure/data/appconfiguration/ConfigurationAsyncClientTest.java	Adds async tests for HEAD paging and ETag change detection.
sdk/appconfiguration/azure-data-appconfiguration/src/samples/java/com/azure/data/appconfiguration/CheckConfigurationSettingsForChanges.java	New sample demonstrating HEAD-based change detection using page ETags + `If-None-Match`.
sdk/appconfiguration/azure-data-appconfiguration/src/main/java/com/azure/data/appconfiguration/package-info.java	Updates package-level instantiation snippets.
sdk/appconfiguration/azure-data-appconfiguration/src/main/java/com/azure/data/appconfiguration/ConfigurationClientBuilder.java	Updates builder JavaDoc instantiation/pipeline snippets.
sdk/appconfiguration/azure-data-appconfiguration/CHANGELOG.md	Documents the new `checkConfigurationSettings` feature.

Copilot · 2026-04-22T19:27:05Z

+    // Parse the 'after' query parameter value from the Link header.
+    // Link header format: </kv?api-version=2023-10-01&$Select=&after=a2V5MTg4Cg%3D%3D>; rel="next"
+    public static String parseAfterParam(String linkHeader) {
+        String nextLink = parseNextLink(linkHeader);
+        if (nextLink == null) {
+            return null;
+        }
+        int afterIdx = nextLink.indexOf("after=");
+        if (afterIdx == -1) {
+            return null;
+        }
+        String afterValue = nextLink.substring(afterIdx + 6);
+        int ampIdx = afterValue.indexOf('&');
+        return ampIdx != -1 ? afterValue.substring(0, ampIdx) : afterValue;


parseAfterParam returns the raw after value from the Link URL (e.g. ...after=a2V5...%3D%3D). The service proxy will URL-encode query params (since @QueryParam(encoded=false)), so passing an already-encoded value will double-encode (% -> %25) and break pagination. Decode the extracted value (e.g., URL-decode) before using it as the After query param continuation token.

Copilot · 2026-04-22T19:27:05Z

 import com.azure.core.exception.ResourceModifiedException;
 import com.azure.core.exception.ResourceNotFoundException;
 import com.azure.core.http.HttpResponse;
+import com.azure.core.http.HttpHeaderName;


HttpHeaderName is imported but never used (it only appears fully-qualified in Javadoc). Unused imports fail compilation; remove this import or use the type in code/Javadoc without the fully-qualified reference.

Suggested change

import com.azure.core.http.HttpHeaderName;

Copilot · 2026-04-22T19:27:06Z

+ *     .credential&#40;new DefaultAzureCredentialBuilder&#40;&#41;.build&#40;&#41;&#41;
+ *     .endpoint&#40;endpoint&#41;


The  instantiation snippet content no longer matches the source snippet in ConfigurationClientJavaDocCodeSnippets.java (which still uses .connectionString(connectionString)). The codesnippet Maven plugin will fail validation/injection during build; update the snippet source (BEGIN/END block) instead, or revert this embedded code to match it.

Suggested change

* .credential(new DefaultAzureCredentialBuilder().build())

* .endpoint(endpoint)

* .connectionString(connectionString)

Copilot · 2026-04-22T19:27:06Z

+     * <p>Check all settings that use the key "prodDBConnection".</p>
+     *
+     * <!-- src_embed com.azure.data.applicationconfig.configurationclient.checkConfigurationSettings#settingSelector-context -->
+     * <!-- src_embed com.azure.data.applicationconfig.configurationclient.checkConfigurationSettings#settingSelector-context -->


Duplicate  marker line will confuse the codesnippet injection/validation step. Remove the extra src_embed line so there is exactly one start marker paired with the .

Suggested change

*

Copilot · 2026-04-22T19:27:06Z

@@ -82,7 +83,8 @@
 * <!-- src_embed com.azure.data.applicationconfig.configurationclient.instantiation -->
 * <pre>
 * ConfigurationClient configurationClient = new ConfigurationClientBuilder&#40;&#41;
- *     .connectionString&#40;connectionString&#41;
+ *     .credential&#40;new DefaultAzureCredentialBuilder&#40;&#41;.build&#40;&#41;&#41;
+ *     .endpoint&#40;endpoint&#41;
 *     .buildClient&#40;&#41;;
 * </pre>
 * <!-- end com.azure.data.applicationconfig.configurationclient.instantiation -->


The instantiation src_embed blocks were edited directly, but the corresponding snippet sources in ConfigurationClientJavaDocCodeSnippets.java still use connection strings (and the codesnippet Maven plugin expects them to stay in sync). Update the // BEGIN: / // END: snippet source and let injection update this JavaDoc, otherwise snippet validation will fail.

Copilot · 2026-04-22T19:27:07Z

+     * <!-- src_embed com.azure.data.applicationconfig.configurationclient.checkConfigurationSettings#settingSelector-context -->
+     * <!-- src_embed com.azure.data.applicationconfig.configurationclient.checkConfigurationSettings#settingSelector-context -->
+     * <pre>
+     * SettingSelector selector = new SettingSelector&#40;&#41;.setKeyFilter&#40;&quot;my-app&#47;*&quot;&#41;;
+     * Context ctx = new Context&#40;key1, value1&#41;;


This src_embed ID for the context overload (...checkConfigurationSettings#settingSelector-context) doesn’t appear to exist as a // BEGIN: / // END: snippet in the module sources. Add the missing snippet to the *JavaDocCodeSnippets.java sources so codesnippet validation passes.

Copilot · 2026-04-22T19:27:08Z

+ *     .credential&#40;new DefaultAzureCredentialBuilder&#40;&#41;.build&#40;&#41;&#41;
+ *     .endpoint&#40;endpoint&#41;


The instantiation src_embed block content here was changed to use credential() + endpoint(), but the snippet source (ConfigurationClientJavaDocCodeSnippets.java, BEGIN: com.azure.data.applicationconfig.async.configurationclient.instantiation) still uses .connectionString(connectionString). Update the snippet source and let the codesnippet plugin inject, otherwise builds will fail snippet validation.

Suggested change

* .credential(new DefaultAzureCredentialBuilder().build())

* .endpoint(endpoint)

* .connectionString(connectionString)

Copilot · 2026-04-22T19:27:08Z

+     * <!-- src_embed com.azure.data.appconfiguration.configurationasyncclient.checkConfigurationSettings -->
+     * <pre>
+     * SettingSelector selector = new SettingSelector&#40;&#41;.setKeyFilter&#40;&quot;my-app&#47;*&quot;&#41;;
+     * client.checkConfigurationSettings&#40;selector&#41;
+     *     .byPage&#40;&#41;
+     *     .subscribe&#40;page -&gt; &#123;
+     *         System.out.println&#40;&quot;Status code: &quot; + page.getStatusCode&#40;&#41;&#41;;
+     *         System.out.println&#40;&quot;Page ETag: &quot; + page.getHeaders&#40;&#41;.getValue&#40;com.azure.core.http.HttpHeaderName.ETAG&#41;&#41;;
+     *     &#125;&#41;;
+     * </pre>
+     * <!-- end com.azure.data.appconfiguration.configurationasyncclient.checkConfigurationSettings -->


The new JavaDoc snippet reference com.azure.data.appconfiguration.configurationasyncclient.checkConfigurationSettings has no matching // BEGIN: / // END: snippet in the module sources. Add the snippet to the *JavaDocCodeSnippets.java file (or remove the src_embed markers) to avoid codesnippet plugin failures.

Copilot · 2026-04-22T19:27:08Z

@@ -48,7 +49,8 @@
 * <!-- src_embed com.azure.data.applicationconfig.configurationclient.instantiation -->
 * <pre>
 * ConfigurationClient configurationClient = new ConfigurationClientBuilder&#40;&#41;
- *     .connectionString&#40;connectionString&#41;
+ *     .credential&#40;new DefaultAzureCredentialBuilder&#40;&#41;.build&#40;&#41;&#41;
+ *     .endpoint&#40;endpoint&#41;
 *     .buildClient&#40;&#41;;
 * </pre>


The instantiation src_embed blocks here don’t match the snippet sources in ConfigurationClientJavaDocCodeSnippets.java (they still use .connectionString(connectionString)). This will fail the codesnippet Maven plugin validation/injection during build; update the snippet sources (BEGIN/END) instead of editing embedded code directly.

Copilot · 2026-04-22T19:27:08Z

 * <!-- src_embed com.azure.data.applicationconfig.configurationclient.instantiation -->
 * <pre>
 * ConfigurationClient configurationClient = new ConfigurationClientBuilder&#40;&#41;
- *     .connectionString&#40;connectionString&#41;
+ *     .credential&#40;new DefaultAzureCredentialBuilder&#40;&#41;.build&#40;&#41;&#41;
+ *     .endpoint&#40;endpoint&#41;
 *     .buildClient&#40;&#41;;
 * </pre>


This instantiation snippet is referenced as a connection-string example in the surrounding package docs, but the code shown uses Entra ID (credential() + endpoint()). Please align the example and narrative so users aren’t misled about required inputs/authentication.

Head Requests

f0f853a

Copilot AI review requested due to automatic review settings April 22, 2026 19:18

mrm9084 requested review from a team, alzimmermsft, avanigupta, nroutray and rossgrambo as code owners April 22, 2026 19:18

github-actions Bot added the App Configuration Azure.ApplicationModel.Configuration label Apr 22, 2026

Copilot started reviewing on behalf of mrm9084 April 22, 2026 19:19 View session

Copilot AI reviewed Apr 22, 2026

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App Config - Head Requests#48899

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		* .credential(new DefaultAzureCredentialBuilder().build())
		* .endpoint(endpoint)

	* .credential(new DefaultAzureCredentialBuilder().build())
	* .endpoint(endpoint)
	* .connectionString(connectionString)

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mrm9084 commented Apr 22, 2026

Description

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