On this page:
http://java.sun.com/j2se/1.5.0/docs/api/java/nio/charset/Charset.html

is a broken link to Character.java, which should be to Character.html.

The typo is in this doc comment for java/nio/charset/Charset.java

/**
 * A named mapping between sequences of sixteen-bit Unicode <a
 * href="../../lang/Character.java#unicode">code units</a> and sequences of
 * bytes. This class defines methods for creating decoders and encoders and

The fix is to just change ".java" to ".html" above.