The links
{link java.io.FileDescriptor#valid() invalid}
need an extra "@".

FileOutputStream constructors are inconsistent,
sometimes referring to "file output stream", and
sometimes to "output file stream".

Fields that can be made final should be.

The following comment seems to be divorced from reality.
     /**
-     * The system dependent file descriptor. The value is
-     * 1 more than actual file descriptor. This means that
-     * the default value 0 indicates that the file is not open.
+     * The system dependent file descriptor.
      */

It's considered very bad style to refer to static fields through
instance syntax.

     protected void finalize() throws IOException {
-	if ((fd != null) &&  (fd != fd.in)) {
-
+	if ((fd != null) &&  (fd != FileDescriptor.in)) {
 	    /*
Posted Date : 2007-11-19 05:16:51.0

N/A

Yes.
Posted Date : 2007-11-19 05:16:51.0