Select Many choice list gives null pointer exception in the value listener method

Question

I have a Select Many Choice component in my page and  I have a method assigned as a value change listener. When ever I select a single value or multiple values I am getting a null pointer exception.
<MessageFactory> <getMessage>
java.lang.NullPointerException
    at oracle.adfinternal.view.faces.model.binding.FacesCtrlListBinding.findIndexFromObject(FacesCtrlListBinding.java:390)
    at oracle.adfinternal.view.faces.model.binding.FacesCtrlListBinding.setInputValue(FacesCtrlListBinding.java:449)
    at oracle.jbo.uicli.binding.JUCtrlValueBinding.put(JUCtrlValueBinding.java:2546)
    at oracle.jbo.uicli.binding.JUCtrlListBinding.put(JUCtrlListBinding.java:3437)
    at javax.el.MapELResolver.setValue(MapELResolver.java:229)
    at com.sun.faces.el.DemuxCompositeELResolver._setValue(DemuxCompositeELResolver.java:255)
    at com.sun.faces.el.DemuxCompositeELResolver.setValue(DemuxCompositeELResolver.java:281)
    at com.sun.el.parser.AstValue.setValue(Unknown Source)
    at com.sun.el.ValueExpressionImpl.setValue(Unknown Source)
    at com.sun.faces.facelets.el.TagValueExpression.setValue(TagValueExpression.java:131)
    at org.apache.myfaces.trinidad.component.UIXEditableValue.updateModel(UIXEditableValue.java:361)
    at org.apache.myfaces.trinidad.component.UIXEditableValue.processUpdates(UIXEditableValue.java:311)
    at Reportview.backing.Report_v1.onRegionSelect(Report_v1.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.el.parser.AstValue.invoke(Unknown Source)
    at com.sun.el.MethodExpressionImpl.invoke(Unknown Source)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    at javax.faces.event.MethodExpressionValueChangeListener.processValueChange(MethodExpressionValueChangeListener.java:144)
    at javax.faces.event.ValueChangeEvent.processListener(ValueChangeEvent.java:134)
    at org.apache.myfaces.trinidad.component.UIXComponentBase.broadcast(UIXComponentBase.java:824)
    at org.apache.myfaces.trinidad.component.UIXEditableValue.broadcast(UIXEditableValue.java:243)
    at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.broadcastEvents(LifecycleImpl.java:1137)
    at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl._executePhase(LifecycleImpl.java:405)
    at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:202)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:508)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
    at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
    at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300)
    at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at oracle.adf.model.servlet.ADFBindingFilter.doFilter(ADFBindingFilter.java:173)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at oracle.adfinternal.view.faces.webapp.rich.RegistrationFilter.doFilter(RegistrationFilter.java:125)
    at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:468)
    at oracle.adfinternal.view.faces.activedata.AdsFilter.doFilter(AdsFilter.java:60)
    at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:468)
    at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl._doFilterImpl(TrinidadFilterImpl.java:293)
    at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl.doFilter(TrinidadFilterImpl.java:199)
    at org.apache.myfaces.trinidad.webapp.TrinidadFilter.doFilter(TrinidadFilter.java:92)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at oracle.adf.library.webapp.LibraryFilter.doFilter(LibraryFilter.java:180)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at oracle.security.jps.ee.http.JpsAbsFilter$1.run(JpsAbsFilter.java:119)
    at java.security.AccessController.doPrivileged(Native Method)
    at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:315)
    at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:442)
    at oracle.security.jps.ee.http.JpsAbsFilter.runJaasMode(JpsAbsFilter.java:103)
    at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:171)
    at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:71)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at oracle.dms.servlet.DMSServletFilter.doFilter(DMSServletFilter.java:139)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
    at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3715)
    at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3681)
    at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
    at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
    at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2277)
    at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2183)
    at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1454)
    at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
    at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)
Can someone tell me why this error occurs.My method is like this -
public void onSelect(ValueChangeEvent event) {
event.getComponent().processUpdates(FacesContext.getCurrentInstance());
String[] s = (String[])event.getNewValue();
System.out.println("Value changed value change ==>> "+s.length+"===>>"+Arrays.toString(s));

Answer 1

Do you get the same results if you try queuing the event to happen after the model update?
// Requeue the event so that it happens after the model update
    if (!PhaseId.INVOKE_APPLICATION.equals(valueChangeEvent.getPhaseId())) {
valueChangeEvent.setPhaseId(PhaseId.INVOKE_APPLICATION);
valueChangeEvent.queue();
    } else {     
     String[] s = (String[])event.getNewValue();
    System.out.println("Value changed value change ==>> "+s.length+"===>>"+Arrays.toString(s));