And the SUN AS is right. :)
Your JSP has not been spec compliant, and therefore not portable across spec compliant JSP containers.
According to JSP.1-8 ("Page Directive Attributes"), only the java.lang.*, javax.servlet.*, javax.servlet.jsp.*, and javax.servlet.http.* packages are imported by the container. Any other packages (including java.util.*) must be imported by the page author through an "import" page directive.
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