Null pointer exception when parsing XML

Question

DOM.Document xmlDOC = new DOM.Document();
xmlDOC.load(xmlstring); 
DOM.XMLNode rootElement = xmlDOC.getRootElement();
for(DOM.XMLNode xmlnodeobj:xmlDOC.getRootElement().getChildElements()){
    For(Quote_line_item__c q:q1){   
        if(q.Name==xmlnodeobj.getChildElement('REF',null).getText()){
            q.Current_Stock__c= xmlnodeobj.getChildElement('QUANTITY',null).getText();
        }
    }
}

Sample XML string:

XMLString='<RESULT><LINE><REF>12600</REF><QUANTITY>980</QUANTITY></LINE><LINE><REF>12601</REF><QUANTITY>3254</QUANTITY></LINE></RESULT>';

Exception : Visualforce Error Help for this Page

System.NullPointerException: Attempt to de-reference a null object Class.createorder.: line 128, column 1 xmlnodeobj.getChildElement('REF',null).getText()

Null pointer exception coming from this statement.

Can any body help me regarding this?

Answer 1

In the code you should check for NULL condition as:

   DOM.Document xmlDOC = new DOM.Document(); 
   xmlDOC.load(xmlstring); 
   DOM.XMLNode rootElement = xmlDOC.getRootElement();
   for(DOM.XMLNode xmlnodeobj:xmlDOC.getRootElement().getChildElements()){
    if(xmlnodeobj.getChildElement('REF',null) != null) // CHECK FOR NULL
      for(Quote_line_item__c q:q1){   
        if(q.Name==xmlnodeobj.getChildElement('REF',null).getText()){
          q.Current_Stock__c=     xmlnodeobj.getChildElement('QUANTITY',null).getText();

      }
    }
   }       

it seems like you are skipping <LINE> and trying to parse directly REF.