For a number of years we have been using Doc Check Doclet version 1.2 beta 2 ([http://java.sun.com/j2se/javadoc/doccheck/]) to check our Javadoc (Java 1.4.2) but now we have upgraded to Java 6 and the Doc Check Doclet doesn't fully understand the new language constructs (enums, etc.).
Obviously, only a Sun official could answer this question. However, I think it safe to assume that Sun will not update this doclet. After all, the doclet API was changed some four or five years ago (with the release of Java 1.5).
AFAIK, the Doc Check Doclet download comes with source code, so you could always update the doclet yourself.