public java.util.List<Message> getMessages() {
        return messages;
    }
<p>
The list of messages to be sent. Each message has the format: { "messageId": "string", "payload": "string"}.
</p>
<p>
The field names of message payloads (data) that you send to IoT Analytics:
</p>
<ul>
<li>
<p>
Must contain only alphanumeric characters and undescores (_). No other special characters are allowed.
</p>
</li>
<li>
<p>
Must begin with an alphabetic character or single underscore (_).
</p>
</li>
<li>
<p>
Cannot contain hyphens (-).
</p>
</li>
<li>
<p>
In regular expression terms: "^[A-Za-z_]([A-Za-z0-9]*|[A-Za-z0-9][A-Za-z0-9_]*)$".
</p>
</li>
<li>
<p>
Cannot be more than 255 characters.
</p>
</li>
<li>
<p>
Are case insensitive. (Fields named foo and FOO in the same payload are considered duplicates.)
</p>
</li>
</ul>
<p>
For example, {"temp_01": 29} or {"_temp_01": 29} are valid, but {"temp-01": 29}, {"01_temp": 29} or {"__temp_01":
29} are invalid in message payloads.
</p>

@return The list of messages to be sent. Each message has the format: { "messageId": "string", "payload":
        "string"}.</p>
        <p>
        The field names of message payloads (data) that you send to IoT Analytics:
        </p>
        <ul>
        <li>
        <p>
        Must contain only alphanumeric characters and undescores (_). No other special characters are allowed.
        </p>
        </li>
        <li>
        <p>
        Must begin with an alphabetic character or single underscore (_).
        </p>
        </li>
        <li>
        <p>
        Cannot contain hyphens (-).
        </p>
        </li>
        <li>
        <p>
        In regular expression terms: "^[A-Za-z_]([A-Za-z0-9]*|[A-Za-z0-9][A-Za-z0-9_]*)$".
        </p>
        </li>
        <li>
        <p>
        Cannot be more than 255 characters.
        </p>
        </li>
        <li>
        <p>
        Are case insensitive. (Fields named foo and FOO in the same payload are considered duplicates.)
        </p>
        </li>
        </ul>
        <p>
        For example, {"temp_01": 29} or {"_temp_01": 29} are valid, but {"temp-01": 29}, {"01_temp": 29} or
        {"__temp_01": 29} are invalid in message payloads.
aws-java-sdk-iotanalytics/src/main/java/com/amazonaws/services/iotanalytics/model/BatchPutMessageRequest.java