What is the difference between and ?

<c:if is a simple if-clause. <c:when> has options for multiple if-clauses and an else clause. Compare:

<c:if test="${foo == 'bar'}">...</c:if>

with

<c:choose>
   <c:when test="${foo == 'bar'}">...</c:when>
   <c:when test="${foo == 'baz'}">...</c:when>
   <c:otherwise>...</c:otherwise>
</c:choose>