public String getPreferredMaintenanceWindow() {
        return this.preferredMaintenanceWindow;
    }
<p>
The weekly time range during which system maintenance can occur.
</p>
<p>
Valid for Cluster Type: Aurora DB clusters and Multi-AZ DB clusters
</p>
<p>
The default is a 30-minute window selected at random from an 8-hour block of time for each Amazon Web Services
Region, occurring on a random day of the week. To see the time blocks available, see <a href=
"https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_UpgradeDBInstance.Maintenance.html#AdjustingTheMaintenanceWindow.Aurora"
> Adjusting the Preferred DB Cluster Maintenance Window</a> in the <i>Amazon Aurora User Guide</i>.
</p>
<p>
Constraints:
</p>
<ul>
<li>
<p>
Must be in the format <code>ddd:hh24:mi-ddd:hh24:mi</code>.
</p>
</li>
<li>
<p>
Days must be one of <code>Mon | Tue | Wed | Thu | Fri | Sat | Sun</code>.
</p>
</li>
<li>
<p>
Must be in Universal Coordinated Time (UTC).
</p>
</li>
<li>
<p>
Must be at least 30 minutes.
</p>
</li>
</ul>

@return The weekly time range during which system maintenance can occur.</p>
        <p>
        Valid for Cluster Type: Aurora DB clusters and Multi-AZ DB clusters
        </p>
        <p>
        The default is a 30-minute window selected at random from an 8-hour block of time for each Amazon Web
        Services Region, occurring on a random day of the week. To see the time blocks available, see <a href=
        "https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_UpgradeDBInstance.Maintenance.html#AdjustingTheMaintenanceWindow.Aurora"
        > Adjusting the Preferred DB Cluster Maintenance Window</a> in the <i>Amazon Aurora User Guide</i>.
        </p>
        <p>
        Constraints:
        </p>
        <ul>
        <li>
        <p>
        Must be in the format <code>ddd:hh24:mi-ddd:hh24:mi</code>.
        </p>
        </li>
        <li>
        <p>
        Days must be one of <code>Mon | Tue | Wed | Thu | Fri | Sat | Sun</code>.
        </p>
        </li>
        <li>
        <p>
        Must be in Universal Coordinated Time (UTC).
        </p>
        </li>
        <li>
        <p>
        Must be at least 30 minutes.
        </p>
        </li>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/model/CreateDBClusterRequest.java