<p:spinner id="s1" min="1" max="#{documentoMB.tamanho}" styleClass="spinner"
valueChangeListener="#{documentoMB.spinnerValueChange}" onchange="submit()"
value="#{documentoMB.valorSpinner}" /> nesse trecho de codigo de minha app, o spinner dispara null exception quando o valor muda. Não sei por que. Alguém sabe? 
stack trace
Advertência: Erro de argumento: O parâmetro targetClass é nulo
java.lang.NullPointerException: Erro de argumento: O parâmetro targetClass é nulo
at com.sun.faces.util.Util.notNull(Util.java:299)
at com.sun.faces.application.ApplicationImpl.createConverter(ApplicationImpl.java:1328)
at org.primefaces.component.spinner.SpinnerRenderer.getConvertedValue(SpinnerRenderer.java:124)
at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
at javax.faces.component.UIInput.validate(UIInput.java:960)
at javax.faces.component.UIInput.executeValidate(UIInput.java:1233)
at javax.faces.component.UIInput.processDecodes(UIInput.java:665)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at org.primefaces.component.tabview.TabView.processDecodes(TabView.java:243)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIForm.processDecodes(UIForm.java:225)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:933)
at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at br.ged.filter.GedFilter.doFilter(GedFilter.java:44)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)