public void setPreferredMaintenanceWindow(String preferredMaintenanceWindow) {
        this.preferredMaintenanceWindow = preferredMaintenanceWindow;
    }
<p>
Configures the maintenance window that you want for the runtime environment. The maintenance window must have the
format <code>ddd:hh24:mi-ddd:hh24:mi</code> and must be less than 24 hours. The following two examples are valid
maintenance windows: <code>sun:23:45-mon:00:15</code> or <code>sat:01:00-sat:03:00</code>.
</p>
<p>
If you do not provide a value, a random system-generated value will be assigned.
</p>

@param preferredMaintenanceWindow
       Configures the maintenance window that you want for the runtime environment. The maintenance window must
       have the format <code>ddd:hh24:mi-ddd:hh24:mi</code> and must be less than 24 hours. The following two
       examples are valid maintenance windows: <code>sun:23:45-mon:00:15</code> or
       <code>sat:01:00-sat:03:00</code>. </p>
       <p>
       If you do not provide a value, a random system-generated value will be assigned.
aws-java-sdk-mainframemodernization/src/main/java/com/amazonaws/services/mainframemodernization/model/UpdateEnvironmentRequest.java