Add values to arraylist use JSTL

JSTL is not designed to do this kind of stuff. This really belongs in the business logic which is (in)directly to be controlled by a servlet class.

Create a servlet which does like:

protected void doGet(HttpServletRequest request, HttpServletResponse response) {
    List<String> animals = new ArrayList<String>();
    animals.add("Sylvester");
    animals.add("Goofy");
    animals.add("Mickey");
    request.setAttribute("animals", animals);
    request.getRequestDispatcher("/WEB-INF/animals.jsp").forward(request, response);
}

Map this on an url-pattern of /animals.

Now create a JSP file in /WEB-INF/animals.jsp (place it in WEB-INF to prevent direct access):

<c:forEach items="${animals}" var="animal">
    ${animal}<br>
</c:forEach>

No need for jsp:useBean as servlet has already set it.

Now call the servlet+JSP by http://example.com/context/animals.

To do add() to a List or others methods from Map, Set, etc... You have to use a unusable variable.

<jsp:useBean id="list" class="java.util.ArrayList"/>
<c:set var="noUse" value="${list.add('YourThing')}"/>
<c:out value="${list}"/>