feat(java): add deleteFolderRecursive sample

This adds a sample demonstrating how to recursively delete a folder in a hierarchical namespace bucket.

Fixes: b/521168740

[Generated-by: AI]

Author: nidhiii-27

java-storage/samples/snippets/src/main/java/com/example/storage/control/v2/DeleteFolderRecursive.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.storage.control.v2;
+
+// [START storage_control_delete_folder_recursive]
+
+import com.google.storage.control.v2.DeleteFolderRecursiveRequest;
+import com.google.storage.control.v2.FolderName;
+import com.google.storage.control.v2.StorageControlClient;
+import java.util.concurrent.ExecutionException;
+
+public final class DeleteFolderRecursive {
+
+  public static void deleteFolderRecursive(String bucketName, String folderName)
+      throws ExecutionException, InterruptedException, Exception {
+    // The name of the bucket
+    // String bucketName = "your-unique-bucket-name";
+
+    // The name of the folder within the bucket
+    // String folderName = "your-unique-folder-name";
+
+    try (StorageControlClient storageControl = StorageControlClient.create()) {
+
+      // Set project to "_" to signify globally scoped bucket
+      String folderResourceName = FolderName.format("_", bucketName, folderName);
+      DeleteFolderRecursiveRequest request =
+          DeleteFolderRecursiveRequest.newBuilder().setName(folderResourceName).build();
+
+      storageControl.deleteFolderRecursiveAsync(request).get();
+
+      System.out.printf("Deleted folder recursively: %s%n", folderResourceName);
+    }
+  }
+}
+// [END storage_control_delete_folder_recursive]

java-storage/samples/snippets/src/test/java/com/example/storage/control/v2/FoldersTest.java

@@ -139,6 +139,20 @@ public void deleteFolder() throws IOException {
     assertThrows(NotFoundException.class, () -> storageControl.getFolder(folderName));
   }
 
+  @Test
+  public void deleteFolderRecursive() throws Exception {
+    FolderName folderName = FolderName.of("_", bucket.getName(), UUID.randomUUID().toString());
+    Folder gen1 =
+        storageControl.createFolder(
+            BucketName.of("_", bucket.getName()),
+            Folder.getDefaultInstance(),
+            folderName.getFolder());
+
+    DeleteFolderRecursive.deleteFolderRecursive(bucket.getName(), folderName.getFolder());
+    assertThat(stdOut.getCapturedOutputAsUtf8String()).contains(folderName.toString());
+    assertThrows(NotFoundException.class, () -> storageControl.getFolder(folderName));
+  }
+
   @Test
   public void listFolder() throws IOException {
     FolderName folderName = FolderName.of("_", bucket.getName(), UUID.randomUUID().toString());