how to reference a java .class file from a JSP page?

Question

I have the JSP file (/page.jsp) in the root of my app directory. I want to use this class located in /WEB-INF/classes/Helper.class.

I tried using the JSP page import statment with the class name but that didn't work. How can I reference Helper.class so that I can use it my JSP? I don't want to include the class in a package/JAR.

Answer 1

Okay, I didn't know this until I looked it up. The JSP Spec (JSP.11.2 JSP Page Implementation Class) is your friend. You'll need to move that class from the default package.

As of JSP 2.0, it is illegal to refer to any classes from the unnamed (a.k.a. default) package. This may result in a translation error on some containers, specifically those that run in a JDK 1.4 or greater environment. It is unfortunate, but unavoidable, that this will break compatibility with some older JSP applications. However, as of JDK 1.4, importing classes from the unnamed package is not valid (see http://java.sun.com/j2se/1.4/compatibility.html#source for details). Therefore, for forwards compatibility, applications must not rely on the unnamed package. This restriction also applies for all other cases where classes are referenced, such as when specifying the class name for a tag in a TLD