chore: Address code comments

Author: lqiu96

samples/snippets/src/main/java/com/example/bigquerystorage/ReadTimestampArrow.java

@@ -110,9 +110,9 @@ public void close() {
   public static void main(String... args) throws Exception {
     // Sets your Google Cloud Platform project ID.
     String projectId = args[0];
-    Integer snapshotMillis = null;
+    Long snapshotMillis = null;
     if (args.length > 1) {
-      snapshotMillis = Integer.parseInt(args[1]);
+      snapshotMillis = Long.parseLong(args[1]);
     }
 
     try (BigQueryReadClient client = BigQueryReadClient.create()) {
@@ -142,7 +142,7 @@ public static void main(String... args) throws Exception {
         Timestamp t =
             Timestamp.newBuilder()
                 .setSeconds(snapshotMillis / 1000)
-                .setNanos(((snapshotMillis % 1000) * 1000000))
+                .setNanos((int) ((snapshotMillis % 1000) * 1000000))
                 .build();
         TableModifiers modifiers = TableModifiers.newBuilder().setSnapshotTime(t).build();
         sessionBuilder.setTableModifiers(modifiers);

samples/snippets/src/main/java/com/example/bigquerystorage/ReadTimestampAvro.java

@@ -77,9 +77,9 @@ public void processRows(AvroRows avroRows) throws IOException {
   public static void main(String... args) throws Exception {
     // Sets your Google Cloud Platform project ID.
     String projectId = args[0];
-    Integer snapshotMillis = null;
+    Long snapshotMillis = null;
     if (args.length > 1) {
-      snapshotMillis = Integer.parseInt(args[1]);
+      snapshotMillis = Long.parseLong(args[1]);
     }
 
     try (BigQueryReadClient client = BigQueryReadClient.create()) {
@@ -109,7 +109,7 @@ public static void main(String... args) throws Exception {
         Timestamp t =
             Timestamp.newBuilder()
                 .setSeconds(snapshotMillis / 1000)
-                .setNanos(((snapshotMillis % 1000) * 1000000))
+                .setNanos((int) ((snapshotMillis % 1000) * 1000000))
                 .build();
         TableModifiers modifiers = TableModifiers.newBuilder().setSnapshotTime(t).build();
         sessionBuilder.setTableModifiers(modifiers);

samples/snippets/src/main/java/com/example/bigquerystorage/WriteToDefaultStreamTimestampWithArrow.java

@@ -124,17 +124,17 @@ public static void writeToDefaultStreamWithArrow(
     // One time initialization for the worker.
     writer.initialize(parentTable, arrowSchema);
     long initialRowCount = getRowCount(parentTable);
-    BufferAllocator allocator = new RootAllocator();
-
-    // A writer should be used to ingest as much data as possible before teardown.
-    // Append 100 batches.
-    for (int i = 0; i < 100; i++) {
-      try (VectorSchemaRoot root = VectorSchemaRoot.create(arrowSchema, allocator)) {
-        // Each batch has 10 rows.
-        ArrowRecordBatch batch = buildRecordBatch(root, 10);
-
-        // Asynchronous append.
-        writer.append(new ArrowData(arrowSchema, batch));
+    try (BufferAllocator allocator = new RootAllocator()) {
+      // A writer should be used to ingest as much data as possible before teardown.
+      // Append 100 batches.
+      for (int i = 0; i < 100; i++) {
+        try (VectorSchemaRoot root = VectorSchemaRoot.create(arrowSchema, allocator)) {
+          // Each batch has 10 rows.
+          ArrowRecordBatch batch = buildRecordBatch(root, 10);
+
+          // Asynchronous append.
+          writer.append(new ArrowData(arrowSchema, batch));
+        }
       }
     }
     // Final cleanup for the stream during worker teardown.

samples/snippets/src/main/java/com/example/bigquerystorage/WriteToDefaultStreamWithArrow.java

@@ -129,17 +129,17 @@ public static void writeToDefaultStreamWithArrow(
     // One time initialization for the worker.
     writer.initialize(parentTable, arrowSchema);
     long initialRowCount = getRowCount(parentTable);
-    BufferAllocator allocator = new RootAllocator();
-
-    // A writer should be used to ingest as much data as possible before teardown.
-    // Append 100 batches.
-    for (int i = 0; i < 100; i++) {
-      try (VectorSchemaRoot root = VectorSchemaRoot.create(arrowSchema, allocator)) {
-        // Each batch has 10 rows.
-        ArrowRecordBatch batch = buildRecordBatch(root, 10);
-
-        // Asynchronous append.
-        writer.append(new ArrowData(arrowSchema, batch));
+    try (BufferAllocator allocator = new RootAllocator()) {
+      // A writer should be used to ingest as much data as possible before teardown.
+      // Append 100 batches.
+      for (int i = 0; i < 100; i++) {
+        try (VectorSchemaRoot root = VectorSchemaRoot.create(arrowSchema, allocator)) {
+          // Each batch has 10 rows.
+          ArrowRecordBatch batch = buildRecordBatch(root, 10);
+
+          // Asynchronous append.
+          writer.append(new ArrowData(arrowSchema, batch));
+        }
       }
     }
     // Final cleanup for the stream during worker teardown.