public Boolean isApplyDuringMaintenanceWindow() {
        return this.applyDuringMaintenanceWindow;
    }
<p>
Indicates whether to update the runtime environment during the maintenance window. The default is false.
Currently, Amazon Web Services Mainframe Modernization accepts the <code>engineVersion</code> parameter only if
<code>applyDuringMaintenanceWindow</code> is true. If any parameter other than <code>engineVersion</code> is
provided in <code>UpdateEnvironmentRequest</code>, it will fail if <code>applyDuringMaintenanceWindow</code> is
set to true.
</p>

@return Indicates whether to update the runtime environment during the maintenance window. The default is false.
        Currently, Amazon Web Services Mainframe Modernization accepts the <code>engineVersion</code> parameter
        only if <code>applyDuringMaintenanceWindow</code> is true. If any parameter other than
        <code>engineVersion</code> is provided in <code>UpdateEnvironmentRequest</code>, it will fail if
        <code>applyDuringMaintenanceWindow</code> is set to true.
aws-java-sdk-mainframemodernization/src/main/java/com/amazonaws/services/mainframemodernization/model/UpdateEnvironmentRequest.java