title: Amazon DynamoDB putItem returning null
body: <p>I am using AmazonDynamoDBClient putItem method to insert item in DB. return type of putItem is PutItemResult but i m getting it as null.</p>
  
  <pre><code>AmazonDynamoDBClient client = new AmazonDynamoDBClient();
  PutItemRequest r = new PutItemRequest();
  r.addItemEntry("custId",new Attribute Value("101"));
  PutItemResult result = client.putItem(r);
  //result is null
  </code></pre>
  
  <p>Item is inserted successfully in DB but why result is getting as null?</p>