Creating Listbox in java

<window id="win" title="Hello World!!" border="normal" width="200px" apply="com.test.tets">

	<listbox id="listbox" >
	<listhead>
	<listheader label="Name"></listheader>
	<listheader label="Age"></listheader>
	</listhead>
	</listbox>
	
	<button label="add" onClick="win$composer.add()" />	
	<button label="remove" onClick="win$composer.remove()" />	

</window>

package com.test;

import java.util.ArrayList;
import java.util.List;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.*;
public class tets extends GenericForwardComposer {
	
	protected Listbox listbox; // autowired
	private ListModelList list; // the model of the listbox
	
	@Override
	public void doAfterCompose(Component comp) throws Exception {
		super.doAfterCompose(comp);
		
		List<String> data = new ArrayList<String>();
		data.add("Hello");
		data.add("World");
		data.add("!");
		
		list = new ListModelList(data, true); // if live is set to true the data list will also be modified
		
		listbox.setModel(list);
	}
	
	public void remove() {
		if(list.size() > 0)
			list.remove(0);
	}
	
	public void add() {
		list.add("TEST");
	}
	
}