but varStatus is a String, I canot use him like "i", i.e. I canot do mod operation on him, so I cant get it, I have download jstl spec, bat its very poor explanation, with no examples
From the JSTL Spec:
Chapter 6 Iterator Actions 39 6.1.3 Iteration Status <c:forEach> also exposes information relative to the iteration taking place. The example below creates an HTML table with the first column containing the position of the item in the collection, and the second containing the name of the product.
See Chapter 16 �Java APIs" for details on the LoopTagStatus interface exposed by the varStatus attribute.