How to get a index value from foreach loop in jstl

I faced similar problems. After research I understand we have some more options with the varStatus="loop". It can either use a zero based index or one based index:

• The ${loop.index} uses a 0 base index
• The ${loop.count} uses a 1 base index

For Example :

<c:forEach var="currentImage" items="${cityBannerImages}" varStatus="loop">
<picture>
   <source srcset="${currentImage}" media="(min-width: 1000px)"></source>
   <source srcset="${cityMobileImages[loop.count]}" media="(min-width:600px)"></source>
   <img srcset="${cityMobileImages[loop.count]}" alt=""></img>
</picture>
</c:forEach>

For more Info please check this link.

use varStatus to get the index c:forEach varStatus properties

<c:forEach var="categoryName" items="${categoriesList}" varStatus="loop">
    <li><a onclick="getCategoryIndex(${loop.index})" href="#">${categoryName}</a></li>
</c:forEach>