AuFileReader has a next typo:

        if (! (magic == AuFileFormat.AU_SUN_MAGIC) || (magic == AuFileFormat.AU_DEC_MAGIC) ||
            (magic == AuFileFormat.AU_SUN_INV_MAGIC) || (magic == AuFileFormat.AU_DEC_INV_MAGIC) ) {

            // not AU, throw exception
            throw new UnsupportedAudioFileException("not an AU file");
        }

        if ((magic == AuFileFormat.AU_SUN_MAGIC) || (magic == AuFileFormat.AU_DEC_MAGIC)) {
            bigendian = true; // otherwise little-endian
        }

Can you spot a typo? It seems that intention was to support all 4 AU_ types.