add region tag for QuestionAnswer.java (#9335)

* add region tag for QuestionAnswer.java

* fix: remove extraneous region tags; update comments

* fix: ensure that region tag includes the last }

---------

Co-authored-by: Jennifer Davis <sigje@google.com>

vertexai/snippets/src/main/java/vertexai/gemini/QuestionAnswer.java

@@ -16,6 +16,7 @@
 
 package vertexai.gemini;
 
+// [START generativeaionvertexai_non_stream_text_basic]
 import com.google.cloud.vertexai.VertexAI;
 import com.google.cloud.vertexai.api.GenerateContentResponse;
 import com.google.cloud.vertexai.generativeai.GenerativeModel;
@@ -33,18 +34,20 @@ public static void main(String[] args) throws Exception {
     System.out.println(output);
   }
 
-  // Ask a simple question to the model.
+  // Asks a question to the specified Vertex AI Gemini model and returns the generated answer.
   public static String simpleQuestion(String projectId, String location, String modelName)
       throws Exception {
     // Initialize client that will be used to send requests.
     // This client only needs to be created once, and can be reused for multiple requests.
     try (VertexAI vertexAI = new VertexAI(projectId, location)) {
       String output;
       GenerativeModel model = new GenerativeModel(modelName, vertexAI);
-
+      // Send the question to the model for processing.
       GenerateContentResponse response = model.generateContent("Why is the sky blue?");
+      // Extract the generated text from the model's response.
       output = ResponseHandler.getText(response);
       return output;
     }
   }
 }
+// [END generativeaionvertexai_non_stream_text_basic]