Confusing error message when tag file's attribute type is unknown ----------------------------------------------------------------- Key: WFLY-3267 URL: https://issues.jboss.org/browse/WFLY-3267 Project: WildFly Issue Type: Bug Security Level: Public(Everyone can see) Components: Web (Undertow) Affects Versions: 8.0.0.Final Reporter: Paul Benedict Assignee: Remy Maucherat Priority: Trivial I have a JSP tag file that requires a "size" attribute: {code} <%@ attribute name="size" required="true" type="Long" %> {code} Because the type accidentally wasn't a FQN (it should have been a {{java.lang.Long}}), this error was generated: {code} JBWEB004193: Unknown attribute type (size) for attribute Number {code} The message doesn't make any sense. "size" isn't the attribute type and the attribute is not "Number". A possible fix: {code} JBWEB004193: Unknown type (Number) was declared for attribute (size) {code} PS: It's really important to talk about the "declaration" here because the tag file isn't mentioned at all in the exception. The Jasper compiler only reports the enclosing JSP, which makes it look like the problem is with the usage not the tag file itself.