how to compare null in jstl with variable?

Question

The value of y is null, but it always execute otherwise part. part. null is considered as not empty.

<c:choose>
  <c:when test="${empty y}">
   value=""
  </c:when>
<c:otherwise>
 value="${y}"
</c:otherwise>      

Answer 1

If y is string write your code like this

    <c:choose>
        <c:when test="${y==null || y==''}">
          value=""
        </c:when>
        <c:otherwise>
         value="${y}"
        </c:otherwise> 
    </c:choose>