Problemas com Struts [RESOLVIDO]

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import contatos.Contato;
import contatos.ContatoDAO;

public class ListaContatosAction extends Action {
	
	@Override
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {	
		List<Contato> lista = new ContatoDAO().getLista();
		request.setAttribute("contatos", lista);
		return mapping.findForward("lista");
	}
}

<!-- for -->
	<c:forEach	var="contato" items="${contatos}">
		${contato.id } - ${contato.nome }<br>	
	</c:forEach>

<struts-config>		
      <action-mappings>		
            <action path="/listaContatos" type="struts.action.ListaContatosAction">
	                <forward name="lista" path="/lista.jsp"/>
	    </action>			
      </action-mappings>	
</struts-config>

HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Servlet execution threw an exception
root cause
java.lang.AbstractMethodError: oracle.jdbc.driver.OracleResultSetImpl.getNString(Ljava/lang/String;)Ljava/lang/String;
	contatos.ContatoDAO.getLista(ContatoDAO.java:44)
	struts.action.ListaContatosAction.execute(ListaContatosAction.java:23)
	org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
	org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
	org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
	org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
	org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305)
	org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
	org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.20 logs.