Problem in zk validation

 
<zk>
	<window width="100%" height="100%"
		apply="org.zkoss.bind.BindComposer"
		viewModel="@id('vm') @init('com.test.Validation')">

		<toolbar id="listToolbarProcess" sclass="vista" height="20px"
			align="start">

			<toolbarbutton label="Save" onClick="@command('doSave')" ></toolbarbutton>

		</toolbar>

		<vlayout sclass="vertical-scroll" vflex="1">

			<intbox id="priority" value="@bind(vm.value)" maxlength="3"
				constraint="no empty" ></intbox>
				<datebox value="@bind(vm.date)"></datebox>
		</vlayout>

	</window>


</zk>

package com.test;

import java.sql.Timestamp;

import org.zkoss.bind.annotation.AfterCompose;
import org.zkoss.bind.annotation.Command;
import org.zkoss.bind.annotation.ContextParam;
import org.zkoss.bind.annotation.ContextType;
import org.zkoss.zk.ui.Component;

public class Validation {

	/**
	 * @author Himanshu
	 */
	Integer value;

	public Integer getValue() {
		return value;
	}

	public void setValue(Integer value) {
		this.value = value;
	}
Timestamp date;
	public Timestamp getDate() {
	return date;
}

public void setDate(Timestamp date) {
	this.date = date;
}

	@AfterCompose
	public void afterCompose(@ContextParam(ContextType.VIEW) Component view) {

	}

	@Command
	public void doSave() {
		
		System.out.println(" value =" + value);
		System.out.println(" Date Value =" + date);
	}

}