create table user_user (
        locale varchar(10)
    )

package broken.test;

import java.util.Locale;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.Transient;

@Entity
@Table(name = "user_user")
public class User  {

    private Locale locale;
    
    @Column(length = 10)
    public Locale getLocale(){
        return locale;
    }

    public void setLocale(Locale locale){
        this.locale = locale;
    }

    /**
     * Gets user's locale in String form.
     * 
     * @return
     */
    @Transient
    public String getLocaleAsString(){
        return getLocale() != null ? getLocale().toString() : null;
    }

    /**
     * Sets user's locale in String form. String consists of both ISO language
     * code and country (separated with underscore), or just language code.
     * Examples: <tt>fi_FI</tt>, <tt>sv_SE</tt>, <tt>en_US</tt>, <tt>fi</tt>,
     * <tt>no</tt>
     * 
     * @param localeAsString
     */
    public void setLocaleAsString(String localeAsString){
        if(localeAsString != null){
            String[] languageAndCountry = localeAsString.split("_");
            if(languageAndCountry.length == 1){
                setLocale(new Locale(languageAndCountry[0]));
            } else{
                setLocale(new Locale(languageAndCountry[0], languageAndCountry[1]));
            }
        } else{
            setLocale(null);
        }
    }

}

Criteria elements = getSession().createCriteria(User.class);
List<User> entities = elements.list();
System.out.println(entities.get(0).getLocale()); // wuhuu, prints en_US

Criteria elements = getSession().createCriteria(User.class);

// okay, not a free text search, but this is what it translates to
elements.add(Restrictions.eq("locale", "fi_FI"));

List<User> entities = elements.list(); // suddenly throws java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Locale