javadoc creation issue : "bad source file"

I am having an issue creating javadoc for my application, I get an error whenever I extend the Window class.

Here is simplified code to test this, though I get the same error in my real application which builds and runs beautifully, but I would love to generate javadocs.

package javadocfail;

import com.vaadin.ui.Window;

class failwindows extends Window  {

here is the error outside of netbeans/ant.

/usr/java/latest/bin/javadoc -d /tmp/javadoc -classpath lib/vaadin-6.7.1.jar ~/NetBeansProjects/javadocfail/src/javadocfail/ 
Loading source file /home/paquette/NetBeansProjects/javadocfail/src/javadocfail/
Constructing Javadoc information...
lib/vaadin-6.7.1.jar(com/vaadin/ui/ error: cannot access Paintable
import com.vaadin.terminal.gwt.client.Paintable;
  bad source file: lib/vaadin-6.7.1.jar(com/vaadin/terminal/gwt/client/
    file does not contain class com.vaadin.terminal.gwt.client.Paintable
    Please remove or make sure it appears in the correct subdirectory of the sourcepath.
1 error

I am not sure why it says the source file is bad, the file exists in the .jar and it looks to have a Paintable interface.

I have tried other vaadin .jar and I get the same issue. I didn’t see any other posts about this, so I am sure its a problem with something I am doing but I could use some help. Thanks.

Apparently something about jdk1.7.0 is broken with javadoc, I do not get this error message when I switch back to using jdk1.6.0_29, everything looks fine.

I see the same problem with Netbeans 7.1 and JDK 1.7.0

Works after switching back to JDK 1.6.0_24

The new Netbeans 7.4 (Beta) requires a JDK 1.7.x, so we just stumbled into this issue once more…
Is there a solution for this problem?