hello, i have XML files which contain records with the following structure: <payment contractType="1"> <income type="0"> <gr code="1" amount="1506.00"/> <gr code="4" amount="35.00"/> <gr code="10" amount="288.14"/> <de code="3011300" amount="138.72"/> <de code="3081100" amount="48.81"/> <de code="3082400" amount="109.84"/> </income> <netAmount1 value="765.00"/> <netAmount2 value="765.00"/> </payment> each file has many records of type payment and i want the final xml to contain one payment record by adding all the amount values for every differrent code value I think XPath can be used for this, but I never used it before , could someone show me some Java (or else) code for this?