NullPointerException on wdContext.nodeMyNode().getElementAt(i)

Question

This is a strange one...
The following loop throws a NullPointerException :
<br>
   int size = wdContext.nodeZoneList().size(); // size is 42...
   for (int i = 0; i < size; i++)
      // the following throws a NullPointerException when i == 0 !!
      Object obj = wdContext.nodeZoneList().getElementAt(i);
Unless I'm missing something here, shouldn't getElementAt() return valid elements for i=0 to size-1 ??
Anyone with an explanation of what could cause the NullPointerException ?
On an unrelated note; can anyone tell me why my message gets surrounded by [ nobr ] and [ /nobr ] when I post ?

Answer 1

Hi,
Your statement
// the following throws a NullPointerException when i == 0 !!
Do you mean to say that it throws the error only when i=0 and give the expected results for all other values of i?. That's quite impossible.
Also, is the node named 'ZoneList' a model binded node? Is this a parent node in your WD context or is it a child node in your context. If this is a child node and if the singleton property is set to 'true', you may have to access this child node by the code as below
IWDNode nodeZoneList = parentNode.getChildNode("ZoneList",parentNode.getLeadSelection());
int size = nodeZoneList.size(); // size is 42...
for (int i = 0; i < size; i++)
   // the following throws a NullPointerException when i == 0 !!
   IWDNodeElement obj = nodeZoneList.getElementAt(i);
But still the wdContext.nodeZoneList().size() returning 42 and the very same wdContext.nodeZoneList() returning null inside the for loop is strange. Here exception is thrown because 'wdContext.nodeZoneList()' returns null; not because getElementAt(i) returns null. It doesn't matter what getElementAt(i) returns and exception won't be thrown for this returning null.
Kindly also check for the cardinality setting (collection and selection, both) of the node in the WD context.
Regards,
Sudeep