update comments

Author: zhongkechen

sdk/src/main/java/com/amazonaws/lambda/durable/execution/CheckpointBatcher.java

@@ -49,7 +49,7 @@ class CheckpointBatcher {
                 MAX_ITEM_COUNT, MAX_BATCH_SIZE_BYTES, CheckpointBatcher::estimateSize, this::checkpointBatch);
     }
 
-    /** Queues a operation update for batched checkpoint */
+    /** Queues an operation update for batched checkpoint */
     CompletableFuture<Void> checkpoint(OperationUpdate update) {
         logger.debug("Checkpoint request received: Action {}", update.action());
         return checkpointApiRequestBatcher.submit(update, config.getCheckpointDelay());
@@ -139,10 +139,6 @@ private void checkpointBatch(List<OperationUpdate> updates) {
             logger.debug("Durable checkpoint API called (latency={}ns): {}.", System.nanoTime() - startTime, response);
 
             // Notify callback of completion
-            // TODO: sam local backend returns no new execution state when called with zero
-            // updates. WHY?
-            // This means the polling will never receive an operation update and complete
-            // the Phaser.
             checkpointToken = response.checkpointToken();
             if (response.newExecutionState() != null) {
                 // fetch all pages of operations

sdk/src/main/java/com/amazonaws/lambda/durable/execution/ExecutionManager.java

@@ -32,6 +32,7 @@
  *   <li>Phaser management (coordination)
  *   <li>Checkpoint batching (via CheckpointManager)
  *   <li>Polling (for waits and retries)
+ *   <li>operationCounter (to generate the next OperationId)
  * </ul>
  *
  * <p>This is the single entry point for all execution coordination. Internal coordination (polling, checkpointing) uses

sdk/src/test/java/com/amazonaws/lambda/durable/execution/ExecutionManagerTest.java

@@ -50,7 +50,6 @@ void nextOperationId() {
         assertEquals("3", manager.nextOperationId());
     }
 
-
     @Test
     void startsInReplayModeWhenOperationsExist() {
         var manager = createManager(List.of(executionOp(), stepOp("1", OperationStatus.SUCCEEDED)));