The following check seems absurd, it is checking for topFile but the error being reported is something else, this check may need to be performed much earlier in the doclet life cycle.

http://hg.openjdk.java.net/jdk/jdk/file/82767203606e/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDoclet.java#l121