public static double toDouble(ByteBuffer buffer, int offset) {
    return Double.longBitsToDouble(toLong(buffer, offset));
  }
Reads a double value at the given buffer's offset.
@param buffer input byte buffer to read
@param offset offset where double is
@return double value at offset
hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java