How to save server memory? I want to remove "state" as soon as data binding populates read-only View

<zk>
	<window id="mainWin" apply="org.zkoss.bind.BindComposer"
		viewModel="@id('vm') @init('test.TestVM')"
		onCreate="@command('clear')" stubonly="true">
		<label value="@load(vm.msg)" stubonly="true" />
		<label value="@load(vm.msgTwo)" stubonly="true" />
	</window>
</zk>

package test;

import org.zkoss.bind.Binder;
import org.zkoss.bind.annotation.*;
import org.zkoss.zk.ui.*;
public class TestVM {
	Boolean msgRendered = false;
	Boolean msgTwoRendered = false;
	public String getMsg () {
		msgRendered = true;
		return "msg";
	}
	public String getMsgTwo () {
		msgTwoRendered = true;
		return "msgTwo";
	}
	@Command
	public void clear (@ContextParam(ContextType.BINDER) Binder binder) {
		if (msgRendered && msgTwoRendered) {
			// clear data
			msgRendered = null;
			msgTwoRendered = null;

			Desktop d = Executions.getCurrent().getDesktop();
			for (Component c : d.getComponents()) {
				if ("mainWin".equals(c.getId())) {
					// remove binding
					binder.removeBindings(c);
				}
			}
		}
	}
}