If Javadoc has a @link to an imported class that is outside of the set of packages for which javadoc is being generated, it generates wrong output. Javadoc'ing this class (with only package 'a' on the command line)

package a;
import java.util.Set;

public class Foo {
    /** Blah {@link Set} blah */
    public void foo() { }
}

results in the text <CODE> being emitted into the user-visible output.