@Override
  public void init(ByteArrayRef bytes, int start, int length) {
    assert (4 == length);
    data.set(Float.intBitsToFloat(LazyBinaryUtils.byteArrayToInt(bytes
        .getData(), start)));
  }
LazyBinaryObject for float which takes four bytes.
serde/src/java/org/apache/hadoop/hive/serde2/lazybinary/LazyBinaryFloat.java