Hibernate x Spring x funcao SUM

SELECT SUM(cd_qtde_estoque) FROM tb_estoque where id_produto = numeroQualquer;

int total = (Integer) getHibernateTemplate().load("SUM(cd_qtde_estoque) FROM Estoque where produto.id = ?", id);

javax.faces.event.MethodExpressionActionListener processAction
SEVERE: org.springframework.orm.hibernate3.HibernateSystemException: Unknown entity: SUM(cd_qtde_estoque) FROM Estoque where produto.id = ?; nested exception is org.hibernate.MappingException: Unknown entity: SUM(cd_qtde_estoque) FROM Estoque where produto.id = ?
	at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:676)
	at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
	at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:424)
	at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
	at org.springframework.orm.hibernate3.HibernateTemplate.load(HibernateTemplate.java:582)
	at org.springframework.orm.hibernate3.HibernateTemplate.load(HibernateTemplate.java:576)
	at br.com.equus.cinesnack.business.dao.hibernate.HibernateEstoqueDAO.getTotalEstoque(HibernateEstoqueDAO.java:19)
	at br.com.equus.cinesnack.business.service.impl.EstoqueBusinessServiceImpl.getTotalEstoque(EstoqueBusinessServiceImpl.java:23)
	at br.com.equus.cinesnack.web.manager.EstoqueManager.getCalculaTotalEstoque(EstoqueManager.java:220)
	at br.com.equus.cinesnack.web.manager.EstoqueManager.getByIdProduto(EstoqueManager.java:214)
	at br.com.equus.cinesnack.web.manager.ProdutoManager.editAction(ProdutoManager.java:101)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.el.parser.AstValue.invoke(AstValue.java:172)
	at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
	at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:68)
	at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:88)
	at javax.faces.event.ActionEvent.processListener(ActionEvent.java:77)
	at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:743)
	at javax.faces.component.UICommand.broadcast(UICommand.java:368)
	at org.ajax4jsf.component.AjaxActionComponent.broadcast(AjaxActionComponent.java:55)
	at org.ajax4jsf.component.UIDataAdaptor.broadcast(UIDataAdaptor.java:1359)
	at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:317)
	at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:292)
	at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:249)
	at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:462)
	at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97)
	at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
	at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:244)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:154)
	at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:260)
	at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:366)
	at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:493)
	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:191)
	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:293)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
	at java.lang.Thread.run(Unknown Source)
Caused by: org.hibernate.MappingException: Unknown entity: SUM(cd_qtde_estoque) FROM Estoque where produto.id = ?
	at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:550)
	at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:68)
	at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:878)
	at org.hibernate.impl.SessionImpl.load(SessionImpl.java:795)
	at org.springframework.orm.hibernate3.HibernateTemplate$4.doInHibernate(HibernateTemplate.java:588)
	at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:419)
	... 47 more