Primefaces autocomplete-widget immer Fehler: die Eigenschaft 'label' not found on type java.lang.String

public class Item
{

    private String label;
    private String value;

    public String getLabel()
    {
        return label;
    }

    public void setLabel(String label)
    {
        this.label = label;
    }

    public String getValue()
    {
        return value;
    }

    public void setValue(String value)
    {
        this.value = value;
    }
}

import java.util.List;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.ConverterException;

public class ItemConverter implements Converter
{

    @Override
    public Object getAsObject(FacesContext facesContext, UIComponent component, String submittedValue)
    {
        if (submittedValue.trim().equals(""))
        {
            return null;
        }
        else
        {
            itemList = getItemList();

            try
            {
                for (Item item : itemList)
                {
                    if (item.getValue().equalsIgnoreCase(submittedValue))
                    {
                        return item;
                    }
                }

            }
            catch (Exception e)
            {
                throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Conversion Error", "Not a valid item object"));
            }
        }

        return null;
    }

    @Override
    public String getAsString(FacesContext facesContext, UIComponent component, Object value)
    {
        if (value == null || value.equals(""))
        {
            return "";
        }
        else
        {
            return String.valueOf(((Item) value).getValue());
        }
    }
    private static List<Item> itemList;

    private static List<Item> getItemList()
    {
        if (null == itemList)
        {
            refData = getRefData();
            itemList = refData.getTestList();
        }

        return itemList;
    }
    private static RefData refData;

    private static RefData getRefData()
    {
        refData = (RefData) FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("refData");
        if (null == refData)
        {
            refData = new RefData();
            FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("refData", refData);
        }
        return refData;
    }
}

import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.faces.context.FacesContext;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component("testBean")
@Scope("request")
public class TestBean implements Serializable
{

    private RefData refData;
    private LinkedHashMap<String, String> parmMap;

    public TestBean()
    {
    }

    public Map<String, String> getParmMap()
    {
        refData = getRefData();
        return refData.getParmMap();
    }

    public void setParmMap(LinkedHashMap<String, String> m)
    {
        refData = getRefData();
        refData.setParmMap(m);
        storeRefData(refData);
    }

    public void setTestList(List<Item> list) throws Exception
    {
        try
        {
            refData = getRefData();
            refData.setTestList(list);
            storeRefData(refData);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public List<Item> getTestList()
    {
        refData = getRefData();
        return refData.getTestList();
    }

    private static RefData getRefData()
    {
        RefData refData = (RefData) FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("refData");
        if (null == refData)
        {
            refData = new RefData();
            FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("refData", refData);
        }
        return refData;
    }

    private static void storeRefData(RefData r)
    {
        FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("refData", r);
    }
}

import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;

public class RefData implements Serializable
{

    public RefData() //(String key)
    {
    }
    private static final Map<String, String> listBoxEntryMap;

    static
    {
        Map<String, String> m = new LinkedHashMap<String, String>();
        m.put("aaavalue", "aaalabel");
        m.put("bbbvalue", "aablabel");
        m.put("cccvalue", "abblabel");
        m.put("dddvalue", "bbblabel");
        m.put("eeevalue", "bbclabel");
        m.put("fffvalue", "bcclabel");
        m.put("gggvalue", "ccclabel");
        m.put("hhhvalue", "ccalabel");
        m.put("iiivalue", "caalabel");
        m.put("jjjvalue", "aaclabel");
        m.put("kkkvalue", "acclabel");
        m.put("lllvalue", "bbalabel");
        m.put("mmmvalue", "baalabel");

        listBoxEntryMap = Collections.unmodifiableMap(m);
    }
    private Map<String, String> parmMap;

    public Map getParmMap()
    {
        if (null == this.parmMap)
        {
            this.parmMap = new LinkedHashMap<String, String>();
            this.parmMap.put("inputval", "");
        }

        return this.parmMap;
    }

    public void setParmMap(Map m)
    {
        this.parmMap = m;
    }
    List<Item> testList = new ArrayList<Item>();

    public void setTestList(List<Item> data) throws IOException
    {
        testList = data;
    }

    public List<Item> getTestList()
    {
        try
        {
            if (null == testList || testList.isEmpty())
            {
                testList = getListOfItems();
            }

            return testList; //(list);
        }
        catch (Exception ex)
        {
            java.util.logging.Logger.getLogger(RefData.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

    public static List<Item> getListOfItems()
    {
        List<Item> list = null;
        try
        {
            Map<String, String> map = listBoxEntryMap;
            Iterator iter = map.keySet().iterator();

            list = new ArrayList<Item>();
            Item item = null;

            while (iter.hasNext())
            {
                String key = (String) iter.next();
                String val = (String) map.get(key);
                item = new Item();
                item.setLabel(key);
                item.setValue(val);
                list.add(item);
            }
        }
        catch (Exception e)
        {
            System.out.println("Exception during query call..." + e.getMessage());
            e.printStackTrace();
        }

        return list;
    }
}