... is not a registered tag in that namespace?

Today JDeveloper broke my project. I don't know what exactly happened, but putting an ADF Faces tag inside a page resulted in JSP compilation errors, e.g.:

Error: http://xmlns.oracle.com/adf/faces:panelPage is not a registered tag in that namespace.

After a few minutes of trying different things I opened the web.xml file and found the problem:

    <taglib>
        <taglib-uri>
            http://java.sun.com/jsf/core
        </taglib-uri>
        <taglib-location>
            /WEB-INF/lib/jsf-impl.jar
        </taglib-location>
    </taglib>
    <taglib>
        <taglib-uri>
            http://xmlns.oracle.com/adf/faces
        </taglib-uri>
        <taglib-location>
            /WEB-INF/lib/adf-faces-impl.jar
        </taglib-location>
    </taglib>
    <taglib>
        <taglib-uri>
            http://xmlns.oracle.com/adf/faces/html
        </taglib-uri>
        <taglib-location>
            /WEB-INF/lib/adf-faces-impl.jar
        </taglib-location>
    </taglib>

Now that was confusing... Removing that piece of code helped. But how did it appear here? JDev only knows...

One OT to mention here: the code you see above was escaped (to be displayed properly by Blogger) using a very simple and effective tool I've come across recently. Check out Dietmar Aust's blog.

JDeveloper 11g Tech Preview is out!

Check out Shay Shmeltzer's blog for details: http://blogs.oracle.com/shay/2007/05/07#a365