How to submit multiple Line Items in Struts 2?
you was almost there.
Just change the Javascript part where you assign the name attribute, including the index exactly as you do in the iteration:
item.name="id.item";
specification.name="id.specification";
// ecc...
must become
item.name="id["+counts+"].itemname";
specification.name="id["+counts+"].specification";
And you will be good.