Combobox Struts2

Prezados,
Estou precisando criar um combobox no struts 2.
Eu fiz assim:
Minha classe action

public class ControleLogin extends ActionSupport implements SessionAware {
private List<String> cargo;

public String controla(){
cargo = new ArrayList<String>();
    		cargo.add("Vendedor");
    		cargo.add("Gerente");
    		cargo.add("Caixa");
    		return "sucess";
}

get's e set's...

JSP

<tr><td><s:combobox  id="11" name="cargo" list="cargo"  headerValue="-- Selecione o cargo --" headerKey="1" label="Cargo"></s:combobox></td></tr>
					<tr>

Alguém poderia me explicar como fazer o combo e como recuperar seu valor escolhido pelo usuário?
Valeu!

Dá o erro:

SEVERE: Servlet.service() for servlet jsp threw exception
tag 'combobox', field 'list', id '11', name 'cargo': You must specify a collection/array/map/enumeration/iterator. Example: people or people.{name} - [unknown location]
	at org.apache.struts2.components.Component.fieldError(Component.java:231)
	at org.apache.struts2.components.Component.findValue(Component.java:293)
	at org.apache.struts2.components.ComboBox.findListValue(ComboBox.java:164)
	at org.apache.struts2.components.ComboBox.evaluateExtraParams(ComboBox.java:114)
	at org.apache.struts2.components.UIBean.evaluateParams(UIBean.java:780)
	at org.apache.struts2.components.UIBean.end(UIBean.java:481)
	at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:43)
	at org.apache.jsp.incluirFuncionario_jsp._jspx_meth_s_005fcombobox_005f0(incluirFuncionario_jsp.java:564)
	at org.apache.jsp.incluirFuncionario_jsp._jspx_meth_s_005fform_005f0(incluirFuncionario_jsp.java:258)
	at org.apache.jsp.incluirFuncionario_jsp._jspService(incluirFuncionario_jsp.java:130)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Unknown Source)

Seguinte:
renomeie seu atributo List para cargos (não esqueça de alterar no JSP o list para cargos).
Crie um atributo cargo na sua action do tipo String com get e set. Esse atributo será setado com o valor selecionado no combo.
Eu uso s:select ao invés de s:combobox.

Só tem que fazer isso?

Fiz, deu esse erro:

tag 'select', field 'list', id '11', name 'cargo': The requested list key 'cargos' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
	at org.apache.struts2.components.Component.fieldError(Component.java:231)
	at org.apache.struts2.components.Component.findValue(Component.java:293)
	at org.apache.struts2.components.ListUIBean.evaluateExtraParams(ListUIBean.java:79)
	at org.apache.struts2.components.Select.evaluateExtraParams(Select.java:99)
	at org.apache.struts2.components.UIBean.evaluateParams(UIBean.java:780)
	at org.apache.struts2.components.UIBean.end(UIBean.java:481)
	at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:43)
	at org.apache.jsp.incluirFuncionario_jsp._jspx_meth_s_005fselect_005f0(incluirFuncionario_jsp.java:564)
	at org.apache.jsp.incluirFuncionario_jsp._jspx_meth_s_005fform_005f0(incluirFuncionario_jsp.java:258)
	at org.apache.jsp.incluirFuncionario_jsp._jspService(incluirFuncionario_jsp.java:130)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Unknown Source)

Valeu, vou continuar tentando.

To usando JPA, tem que colocar alguma annotation?
Não to mapeando em lugar nenhum, já que estou usando JPA.

Bem, só consegui resolver botando o atributo em session.
Aó peguei no jsp assim:

<s:select list="#session['cargos']" id="cargo" name="cargo" headerValue="-- Selecione o cargo --" headerKey="1" label="Cargo"></s:select>

valeu!