Hi friends, 

Struts provides four major JSTLs(JSP standrads Tag Libraries). They are used as JSP helper. Those tag libraries are descrided in TLD (Tag Library Descriptor) files..
1 : struts-html.tld - Tags to help generating HTML elements.
2 : struts-form.tld - Tags to generating HTML FORM elements.
3 : struts-bean.tld - Tags representing some JavaBeans like: cookie, header, message, and page.
4 : struts-logic.tld - Tag representing boolean logic operations.

Thanks.