public static int putLong(byte[] bytes, int offset, long val) {
    if (bytes.length - offset < SIZEOF_LONG) {
      throw new IllegalArgumentException("Not enough room to put a long at" + " offset " + offset
        + " in a " + bytes.length + " byte array");
    }
    return ConverterHolder.BEST_CONVERTER.putLong(bytes, offset, val);
  }
Put a long value out to the specified byte array position.
@param bytes  the byte array
@param offset position in the array
@param val    long to write out
@return incremented offset
@throws IllegalArgumentException if the byte array given doesn't have enough room at the offset
                                 specified.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/Bytes.java