It should be a translation error - during translation, the container does a validation of the document, all URIs and tag library references it contains, and verifies that all tags have the correct body content, attributes, types of attribute values etc. as declared in the TLD. If anything is wrong, you'll get an error at that point - the page isn't even translated into
servlet source code, let alone compiled; so compilation and runtime errors are impossible!
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / Amazon Amazon UK )