What is the difference between and ?

Question

I\'ve noticed usages of in one place of JSP code and in the other. The things they do look the same for me. Are the

Answer 1

<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>

Answer 2

<c:if> doesn't support any kind of "else" or "else if" functionality. <c:when> does. So if you need something analogous to

if (some_condition) {
    // ...
}

then use <c:if>. If you need something analogous to

if (some_condition) {
    // ...
} else if (some_other_condition) {
    // ...
} else {
    // ...
}

then use <c:choose> with <c:when> and (optionally) <c:otherwise>.