How to parse the below xml code?

[Mehmeh]

I have sale tag as child node that exists for multiple times but in that Employee tag doesn't exists for all sale tag.need to parse this xml.Got Null pointer exception when there is no employee tag.How to parse this xml even if some child tag name doesn't exists?\[code\]<?xml version="1.0" encoding="ISO-8859-1"?> <Transactions> <DocumentInfo TransferType="Transactions" Copyright="2010, Hectronic GmbH" CreatedBy="HecPoll"> <CreateDate Year="2011" Month="7" Day="13"/> <CreateTime Hour="6" Minute="0" Second="16"/> </DocumentInfo> <DocumentData> <Sale RcpNum="151" Amount="228.760" Station="1" Customer="000003" Terminal="1"> <Date Year="2011" Month="07" Day="12"/> <Time Hour="07" Minute="23" Second="00"/> <ArticleSale Quantity="6.020" SglPriceAsSold="38.000" SglPriceAsStored="38.000" SglPrice="38.000" Amount="228.760" FCCAmount="228.760" Taxrate="18" LogicalFPNumber="1" TankNumber="3" ArtNum="3" SaleNum="1"/> <Payment PAN="000000002117904490D" Amount="228.760" TenderCode="0" PayNum="1"/> <Employee Lastname="V KALYANI"/> <Vehicle LicensePlate="10K"/> </Sale> <Sale RcpNum="255" Amount="6650.000" Station="1" Customer="ZZZZZZ" Terminal="0"> <Date Year="2011" Month="07" Day="12"/> <Time Hour="07" Minute="24" Second="00"/> <ArticleSale Quantity="175.000" SglPriceAsSold="38.000" SglPriceAsStored="38.000" SglPrice="38.000" Amount="6650.000" FCCAmount="6650.000" Taxrate="19" LogicalFPNumber="1" TankNumber="1" ArtNum="3" SaleNum="1"/> <Payment PAN="000000001885018677D" Amount="6650.000" TenderCode="0" PayNum="1"/> </Sale> <Sale RcpNum="152" Amount="3078.000" Station="1" Customer="000003" Terminal="1"> <Date Year="2011" Month="07" Day="12"/> <Time Hour="07" Minute="27" Second="00"/> <ArticleSale Quantity="81.000" SglPriceAsSold="38.000" SglPriceAsStored="38.000" SglPrice="38.000" Amount="3078.000" FCCAmount="3078.000" Taxrate="18" LogicalFPNumber="1" TankNumber="3" ArtNum="3" SaleNum="1"/> <Payment PAN="000000002117928224D" Amount="3078.000" TenderCode="0" PayNum="1"/> <Employee Lastname="A MUNIYANDI"/> <Vehicle LicensePlate="10F"/> </Sale> </DocumentData></Transactions>\[/code\]Thanks,