Refresh methodIterator cause NullPointerException

Question

HI Guys,
I am using JDeveloper 10.1.3 and experiencing a strange problem with JSF Faces. I have a tree model defined in the pagedef.xml file. Every time I try to refresh the iterator binding, the NullPointerException occurs. It only happens when refreshing, not the first time. acccording to the trace stack, the exception occurs when ADF framework tries to refresh the iterator.
Here is the code to refresh the iterator:
DCIteratorBinding loansBinding = (DCIteratorBinding) bindings.get("findLoansIter");
loansBinding.executeQuery();
The following is the
<methodIterator id="findLoansIter" Binds="findLoans.result"
DataControl="PEPublicLocal" RangeSize="-1"
BeanClass="pe.datamodule.beans.Loan" Refresh="renderModel"
RefreshCondition="${adfFacesContext.postback}"/>
<nodeDefinition DefName="pe.datamodule.beans.Loan" id="LoanNode">
<AttrNames>
<Item Value="dueDate"/>
<Item Value="total"/>
</AttrNames>
<Accessors>
<Item Value="loanextraCollection"/>
</Accessors>
</nodeDefinition>
<nodeDefinition DefName="pe.datamodule.beans.Loanextra"
id="LoanextraNode">
<AttrNames>
<Item Value="amount"/>
<Item Value="loanExtraID"/>
</AttrNames>
</nodeDefinition>
</tree>
The exception is
09/12/17 22:13:17 java.lang.NullPointerException
09/12/17 22:13:17      at oracle.adf.model.generic.RowImpl.internalGetAttributeValue(RowImpl.java:154)
09/12/17 22:13:17      at oracle.adf.model.generic.RowImpl.getAttribute(RowImpl.java:130)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUCtrlValueBinding.internalGetAttributeValueFromRow(JUCtrlValueBinding.java:702)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUCtrlValueBinding.getAttributeFromRow(JUCtrlValueBinding.java:470)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUCtrlValueBinding.getAttributes(JUCtrlValueBinding.java:901)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUCtrlHierNodeBinding.refresh(JUCtrlHierNodeBinding.java:504)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUCtrlHierNodeBinding.updateValuesFromRow(JUCtrlHierNodeBinding.java:523)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUIteratorBinding.updateValuesFromRows(JUIteratorBinding.java:315)
09/12/17 22:13:17      at oracle.adf.model.binding.DCIteratorBinding.refreshControl(DCIteratorBinding.java:695)
09/12/17 22:13:17      at oracle.adf.model.binding.DCIteratorBinding.rangeRefreshed(DCIteratorBinding.java:737)
09/12/17 22:13:17      at oracle.jbo.common.RowSetHelper.fireRangeRefreshed(RowSetHelper.java:172)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.notifyRangeRefreshed(DCRowSetIteratorImpl.java:1570)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.buildProviderIterator(DCRowSetIteratorImpl.java:465)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.fetchDataSource(DCRowSetIteratorImpl.java:394)
09/12/17 22:13:17      at oracle.adf.model.generic.DCGenericRowSetIteratorImpl.notifyNavigationEvent(DCGenericRowSetIteratorImpl.java:331)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.syncIterator(DCRowSetIteratorImpl.java:258)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.first(DCRowSetIteratorImpl.java:653)
09/12/17 22:13:17      at oracle.adf.model.binding.DCIteratorBinding.refreshControl(DCIteratorBinding.java:651)
09/12/17 22:13:17      at oracle.adf.model.binding.DCIteratorBinding.rangeRefreshed(DCIteratorBinding.java:737)
09/12/17 22:13:17      at oracle.jbo.common.RowSetHelper.fireRangeRefreshed(RowSetHelper.java:172)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.notifyRangeRefreshed(DCRowSetIteratorImpl.java:1570)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.buildProviderIterator(DCRowSetIteratorImpl.java:465)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.fetchDataSource(DCRowSetIteratorImpl.java:394)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.getRowAtAbsoluteIndex(DCRowSetIteratorImpl.java:1008)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.syncIterator(DCRowSetIteratorImpl.java:225)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.restoreCurrency(DCRowSetIteratorImpl.java:1821)
09/12/17 22:13:17      at oracle.adf.model.generic.DCRowSetIteratorImpl.rebuildIteratorUpto(DCRowSetIteratorImpl.java:190)
09/12/17 22:13:17      at oracle.adf.model.binding.DCDataControl.rebuildIteratorIfNeeded(DCDataControl.java:1696)
09/12/17 22:13:17      at oracle.adf.model.generic.DCGenericDataControl.executeIteratorBindingIfNeeded(DCGenericDataControl.java:581)
09/12/17 22:13:17      at oracle.adf.model.binding.DCIteratorBinding.executeQueryIfNeeded(DCIteratorBinding.java:1825)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUMethodIteratorDef$JUMethodIteratorBinding.executeQueryIfNeeded(JUMethodIteratorDef.java:289)
09/12/17 22:13:17      at oracle.jbo.uicli.binding.JUMethodIteratorDef$JUMethodIteratorBinding$1.afterInvokeMethod(JUMethodIteratorDef.java:221)
09/12/17 22:13:17      at oracle.adf.model.binding.DCInvokeMethod.notifyAfterInvokeMethod(DCInvokeMethod.java:667)
09/12/17 22:13:17      at oracle.adf.model.binding.DCInvokeMethod.callMethod(DCInvokeMethod.java:228)
Please help! This has bother me for more than a week!
Thanks in advance

Answer 1

Hi Juan,
What do you mean by removing the query? I have the same idea like you do. I tried to close or clear or remove or release the previous query result and it did not work. I did not know whether I did not close the result properly or the refresh did not go properly. Anyway, the exception still show up. I even tried to release the rowSetIterator behind the IteratorBinding, not working.
( this is another question I have. I don't know how to release the query result for a page. I don't want to have the previous page query result show up when I navigate back to the same page. any idea?)
I think the problem is where the framework tries to apply the new query result on the top of the old result and that's why it called refreshControl. The whole problem happend during that refresh control.
If I switch the tree to table, it works immediately. If I adjust the tree to one level, it works immediately. If I only put one attribute at the first level, it works immediately.
Also, I am using JSF/ADF with Toplink and web service. I don't know how to verify whether the model lay works or not. but like I said, the first time work always. or if I intentionally make the query result to be no record, then trying it again always works.
Please help!
thanks
Steven