Using jsp:forward on Tomcat, why do I get the error java.lang.IllegalArgumentException at javax.servlet.http.HttpUtils.parseName(HttpUtils.java:285) ?

[Note: the following may not apply to all versions of Tomcat. Please verify that you are using the latest version. -A]

Tomcat misinterprets jsp:param tag of jsp:forward if the name is represented as variable, i.e.

<jsp:param name="frame" value="bottom"/>

works well but

<jsp:param name="<%= var %>" value="bottom"/>

doesnt. The later is what we had in our code hence the exception.