Target Unreachable -identifier 'row' resolved to null ADF_FACES-60097- Oracle ADF

"row resolved to null" in ADF Faces- is one of the most harassing bug , and still there is no proper reason or solution for it.
recently i was working in an ADF application and this error occurs. I was not able to find root cause . see this crash-

and log on console-

<LifecycleImpl> <_handleException> ADF_FACES-60098:Faces lifecycle receives unhandled exceptions in phase APPLY_REQUEST_VALUES 2
javax.el.PropertyNotFoundException: Target Unreachable, identifier 'row' resolved to null
 at com.sun.el.parser.AstValue.getTarget(Unknown Source)
 at com.sun.el.parser.AstValue.isReadOnly(Unknown Source)
 at com.sun.el.ValueExpressionImpl.isReadOnly(Unknown Source)
 at oracle.adfinternal.view.faces.renderkit.rich.EditableValueRenderer._getUncachedReadOnly(EditableValueRenderer.java:476)
 at oracle.adfinternal.view.faces.renderkit.rich.EditableValueRenderer.getReadOnly(EditableValueRenderer.java:390)
 at oracle.adfinternal.view.faces.renderkit.rich.EditableValueRenderer.wasSubmitted(EditableValueRenderer.java:345)
 at oracle.adfinternal.view.faces.renderkit.rich.EditableValueRenderer.decodeInternal(EditableValueRenderer.java:116)
 at oracle.adfinternal.view.faces.renderkit.rich.SimpleInputDateRenderer.decodeInternal(SimpleInputDateRenderer.java:72)
 at oracle.adfinternal.view.faces.renderkit.rich.LabeledInputRenderer.decodeInternal(LabeledInputRenderer.java:56)
 at oracle.adf.view.rich.render.RichRenderer.decode(RichRenderer.java:342)
 at org.apache.myfaces.trinidad.render.CoreRenderer.decode(CoreRenderer.java:292)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.__rendererDecode(UIXComponentBase.java:1334)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.decode(UIXComponentBase.java:865)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.processDecodes(UIXComponentBase.java:965)
 at org.apache.myfaces.trinidad.component.UIXEditableValue.processDecodes(UIXEditableValue.java:287)
 at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl$ApplyRequestValuesCallback.invokeContextCallback(LifecycleImpl.java:1548)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1735)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1750)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXCollection.invokeOnComponent(UIXCollection.java:1215)
 at oracle.adf.view.rich.component.rich.data.RichTable.invokeOnComponent(RichTable.java:620)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1750)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1750)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnNamingContainerComponent(UIXComponentBase.java:1693)
 at oracle.adf.view.rich.component.fragment.UIXRegion.invokeOnComponent(UIXRegion.java:625)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1750)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnChildrenComponents(UIXComponentBase.java:1627)
 at org.apache.myfaces.trinidad.component.UIXComponentBase.invokeOnComponent(UIXComponentBase.java:1750)
 at org.apache.myfaces.trinidad.component.UIXDocument.invokeOnComponent(UIXDocument.java:106)
 at javax.faces.component.UIComponent.invokeOnComponent(UIComponent.java:1299)
 at javax.faces.component.UIComponentBase.invokeOnComponent(UIComponentBase.java:677)
 at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl._executePhase(LifecycleImpl.java:374)
 at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:204)
 at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312)
 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:122)
 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$1.run(JpsAbsFilter.java:111)
 at java.security.AccessController.doPrivileged(Native Method)
 at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:313)
 at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:413)
 at oracle.security.jps.ee.http.JpsAbsFilter.runJaasMode(JpsAbsFilter.java:94)
 at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:161)
 at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:71)
 at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
 at oracle.dms.servlet.DMSServletFilter.doFilter(DMSServletFilter.java:136)
 at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
 at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
 at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
 at weblogic.servlet.internal.WebAppServletContext$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)
<RegistrationConfigurator> <handleError> ADF_FACES-60096:Server Exception during PPR, #1
javax.el.PropertyNotFoundException: Target Unreachable, identifier 'row' resolved to null 

after lot of probing- finally i have fixed it, and sharing same .

Possible Causes-

• Mainly occurs in editable af:table
• Problem with Primary Key
• af:column's component's property is being used in any EL, inside or outside of table

        Exp- #{row.bindings.xyz.inputValue==0} 

• Updateable primary key, and autosubmit true

Possible Solution -

• Never use primary key as updateable column in af:table, if you have to use then remove primary key from Entity Object
• Try to validate in RowImpl instead of Expression of Table
• Surrogate Primary Key
• Avoid LOV (List of Values) on primary key
• Change Event Policy of af:table and iterator to none

    these solutions are not rules or conventions, you can only try , and may one of it will work for you