Primefaces passar objeto com parametro

Esta dando este erro no console.

Console

ago 15, 2016 9:04:19 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
ADVERTÊNCIA: /homeAluno.xhtml @24,58 actionListener="#{alunoBean.comprarCurso(curso)}": java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.util.Collection]
javax.el.ELException: /homeAluno.xhtml @24,58 actionListener="#{alunoBean.comprarCurso(curso)}": java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.util.Collection]
	at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:111)
	at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:147)
	at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
	at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:814)
	at javax.faces.component.UICommand.broadcast(UICommand.java:300)
	at javax.faces.component.UIData.broadcast(UIData.java:1108)
	at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
	at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
	at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
	at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1110)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:785)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1419)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:44)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.util.Collection]
	at org.hibernate.ejb.AbstractQueryImpl.validateParameterBinding(AbstractQueryImpl.java:375)
	at org.hibernate.ejb.AbstractQueryImpl.registerParameterBinding(AbstractQueryImpl.java:348)
	at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:375)
	at br.com.caelum.livraria.dao.UsuarioDao.cursoJaCadastrado(UsuarioDao.java:81)
	at br.com.caelum.livraria.bean.AlunoBean.comprarCurso(AlunoBean.java:25)
	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:247)
	at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:267)
	at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
	... 33 more

ago 15, 2016 9:04:19 PM com.sun.faces.context.AjaxExceptionHandlerImpl handlePartialResponseError
GRAVE: java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.util.Collection]
	at org.hibernate.ejb.AbstractQueryImpl.validateParameterBinding(AbstractQueryImpl.java:375)
	at org.hibernate.ejb.AbstractQueryImpl.registerParameterBinding(AbstractQueryImpl.java:348)
	at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:375)
	at br.com.caelum.livraria.dao.UsuarioDao.cursoJaCadastrado(UsuarioDao.java:81)
	at br.com.caelum.livraria.bean.AlunoBean.comprarCurso(AlunoBean.java:25)
	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:247)
	at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:267)
	at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
	at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:147)
	at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
	at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:814)
	at javax.faces.component.UICommand.broadcast(UICommand.java:300)
	at javax.faces.component.UIData.broadcast(UIData.java:1108)
	at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
	at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
	at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
	at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1110)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:785)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1419)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:44)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Unknown Source)

homeAluno.xhtml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
	xmlns:h="http://xmlns.jcp.org/jsf/html"
	xmlns:f="http://xmlns.jcp.org/jsf/core"
	xmlns:p="http://primefaces.org/ui"
	xmlns:ui="http://xmlns.jcp.org/jsf/facelets">

<ui:composition template="_templateProfessor.xhtml">

	<ui:define name="titulo">
		<p:outputPanel>Home Professor</p:outputPanel>
	</ui:define>

	<ui:define name="conteudo">

		<p:carousel value="#{crudeCursoBean.cursos}" headerText="Cursos"
			var="curso" itemStyle="text-align:center" responsive="true">
			<p:panelGrid columns="2" style="width:100%;margin:10px 0px"
				columnClasses="label,value" layout="grid"
				styleClass="ui-panelgrid-blank">

				<p:commandButton value="Comprar"
					actionListener="#{alunoBean.comprarCurso(curso)}" />

				<h:outputText value="Id:" />
				<h:outputText value="#{curso.id}" />

				<h:outputText value="Titulo:" />
				<h:outputText value="#{curso.titulo}" />

				<h:outputText value="Preço:" />
				<h:outputText value="#{curso.valor}">
					<f:convertNumber type="currency" pattern="R$ #0.00"
						currencySymbol="R$" locale="pt_BR" />
				</h:outputText>

				<h:outputText value="Descrição" />
				<h:outputText value="#{curso.descricao}" />

			</p:panelGrid>

			<p:dataList id="listaCapitulos"
				value="#{homeProfessorBean.getListaCapitulo(curso)}" var="capitulo"
				type="ordered">
				<f:facet name="header">
            		Capitulos
        		</f:facet>
        		#{capitulo}
        		
        		</p:dataList>

		</p:carousel>
	</ui:define>

</ui:composition>

</html>

AlunoBean.class

package br.com.caelum.livraria.bean;

import java.util.ArrayList;
import java.util.List;

import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.context.FacesContext;

import br.com.caelum.livraria.dao.CursoDao;
import br.com.caelum.livraria.dao.UsuarioDao;
import br.com.caelum.livraria.modelo.Curso;
import br.com.caelum.livraria.modelo.Usuario;

@ManagedBean
@ViewScoped
public class AlunoBean {

	List<Curso> cursos = new ArrayList<Curso>();

	public void comprarCurso(Curso curso) {
		FacesContext context = FacesContext.getCurrentInstance();
		Usuario usuarioAtual = (Usuario) context.getExternalContext().getSessionMap().get("usuarioLogado");
		boolean cadastrado = new UsuarioDao().cursoJaCadastrado(curso);

		if (cadastrado) {
			context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_ERROR, "Erro!", "Aluno já possui Curso."));
		} else {
			cursos.add(curso);
			usuarioAtual.setCursos(cursos);
			new UsuarioDao().adicionaCursoAoUsuario(usuarioAtual);
			context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_INFO, "Parabéns!", "Compra Realizada."));
		}

	}
}

tenta remover o parametro curso Bean.comprarCurso(curso) da EL. obs não olhei sua EL. apenas o log.