This assumes you are already familiar with creating variables using c:set and printing variables using c:out. Let's take an example of a variabled called name that contains a value of Jeremy.
<c:set var="name" value="Jeremy"/>
The following if statement will print "Congratulations. Your name is Jeremy." if name equals Jeremy.
<c:if test="${name == 'Jeremy'}">
Congratulations. Your name is Jeremy.
</c:if>
Running this application should print "Congratulations. Your name is Jeremy."