JSTL arithmetic losing precision -

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• is floating point math broken? 20 answers

why jstl block resulting 0.9999999999999999, , fix?

<c:set var="one" value="0.1"/> <c:set var="two" value="0.7"/> <c:set var="three" value="0.1"/> <c:set var="four" value="0.1"/> <c:out  value="${one+two+three+four}"/> 

jb nizet's comment correct, here's how deal it.

you should consider using fmt:formatnumber function when dealing floating point numbers. here url: http://www.tutorialspoint.com/jsp/jstl_format_formatnumber_tag.htm

and here example:

<c:set var="one" value="0.1"/> <c:set var="two" value="0.7"/> <c:set var="three" value="0.1"/> <c:set var="four" value="0.1"/> <fmt:formatnumber value="${one+two+three+four}" maxfractiondigits="2" /> 

make sure include line @ top of jsp code:

<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>