public String getPreferredMaintenanceWindow() {
        return this.preferredMaintenanceWindow;
    }
<p>
The weekly time range during which system maintenance can occur, in Universal Coordinated Time (UTC).
</p>
<p>
Format: <code>ddd:hh24:mi-ddd:hh24:mi</code>
</p>
<p>
The default is a 30-minute window selected at random from an 8-hour block of time for each Amazon Region,
occurring on a random day of the week.
</p>
<p>
Valid Days: Mon, Tue, Wed, Thu, Fri, Sat, Sun.
</p>
<p>
Constraints: Minimum 30-minute window.
</p>

@return The weekly time range during which system maintenance can occur, in Universal Coordinated Time (UTC).</p>
        <p>
        Format: <code>ddd:hh24:mi-ddd:hh24:mi</code>
        </p>
        <p>
        The default is a 30-minute window selected at random from an 8-hour block of time for each Amazon Region,
        occurring on a random day of the week.
        </p>
        <p>
        Valid Days: Mon, Tue, Wed, Thu, Fri, Sat, Sun.
        </p>
        <p>
        Constraints: Minimum 30-minute window.
aws-java-sdk-neptune/src/main/java/com/amazonaws/services/neptune/model/ModifyDBClusterRequest.java