public void setPreferredBackupWindow(String preferredBackupWindow) {
        this.preferredBackupWindow = preferredBackupWindow;
    }
<p>
The daily time range during which automated backups are created for your database if automated backups are
enabled.
</p>
<p>
Constraints:
</p>
<ul>
<li>
<p>
Must be in the <code>hh24:mi-hh24:mi</code> format.
</p>
<p>
Example: <code>16:00-16:30</code>
</p>
</li>
<li>
<p>
Specified in Coordinated Universal Time (UTC).
</p>
</li>
<li>
<p>
Must not conflict with the preferred maintenance window.
</p>
</li>
<li>
<p>
Must be at least 30 minutes.
</p>
</li>
</ul>

@param preferredBackupWindow
       The daily time range during which automated backups are created for your database if automated backups are
       enabled.</p>
       <p>
       Constraints:
       </p>
       <ul>
       <li>
       <p>
       Must be in the <code>hh24:mi-hh24:mi</code> format.
       </p>
       <p>
       Example: <code>16:00-16:30</code>
       </p>
       </li>
       <li>
       <p>
       Specified in Coordinated Universal Time (UTC).
       </p>
       </li>
       <li>
       <p>
       Must not conflict with the preferred maintenance window.
       </p>
       </li>
       <li>
       <p>
       Must be at least 30 minutes.
       </p>
       </li>
aws-java-sdk-lightsail/src/main/java/com/amazonaws/services/lightsail/model/UpdateRelationalDatabaseRequest.java