Could not initialize proxy - no Session

Front-end
#1

Olá. Estou utilizando hibernate + postgres na minha aplicação. Está dando esse erro: could not initialize proxy - no Session. Só que esse erro não acontece toda hora, sem eu mudar nada o erro aparece.

org.hibernate.LazyInitializationException: could not initialize proxy - no Session
	at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:164)
	at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:285)
	at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
	at Modelo.Produto_$$_javassist_0.getId(Produto_$$_javassist_0.java)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at javax.el.BeanELResolver.getValue(BeanELResolver.java:97)
	at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
	at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
	at org.apache.el.parser.AstValue.getValue(AstValue.java:167)
	at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:187)
	at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
	at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
	at org.primefaces.component.datatable.DataTable.getRowKey(DataTable.java:286)
	at org.primefaces.component.datatable.DataTable.addToSelectedRowKeys(DataTable.java:1034)
	at org.primefaces.component.datatable.DataTable.findSelectedRowKeys(DataTable.java:1011)
	at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:635)
	at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:249)
	at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:211)
	at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:83)
	at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1903)
	at javax.faces.render.Renderer.encodeChildren(Renderer.java:176)
	at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1896)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1899)
	at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:451)
	at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
	at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
	at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:301)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:74)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1015)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:652)
	at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1575)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1533)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)

Esse erro está me perturbando já, alguma sugestão?

#2