public static Class<?> getWALCellCodecClass(Configuration conf) {
    return conf.getClass(WAL_CELL_CODEC_CLASS_KEY, WALCellCodec.class);
  }
Default constructor - <b>all subclasses must implement a constructor with this signature </b>
if they are to be dynamically loaded from the {@link Configuration}.
@param conf        configuration to configure <tt>this</tt>
@param compression compression the codec should support, can be <tt>null</tt> to indicate no
                   compression
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALCellCodec.java