private static Map<byte[], byte[]> createCfRenameMap(Configuration conf) {
    Map<byte[], byte[]> cfRenameMap = null;
    String allMappingsPropVal = conf.get(CF_RENAME_PROP);
    if (allMappingsPropVal != null) {
      // The conf value format should be sourceCf1:destCf1,sourceCf2:destCf2,...
      String[] allMappings = allMappingsPropVal.split(",");
      for (String mapping : allMappings) {
        if (cfRenameMap == null) {
          cfRenameMap = new TreeMap<>(Bytes.BYTES_COMPARATOR);
        }
        String[] srcAndDest = mapping.split(":");
        if (srcAndDest.length != 2) {
          continue;
        }
        cfRenameMap.put(Bytes.toBytes(srcAndDest[0]), Bytes.toBytes(srcAndDest[1]));
      }
    }
    return cfRenameMap;
  }
Attempt to filter out the keyvalue
@param c {@link Cell} on which to apply the filter
@return <tt>null</tt> if the key should not be written, otherwise returns the original
        {@link Cell}
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/Import.java