private void setupOutputFileStreams() throws IOException {
    parentDir = FileUtils.createLocalDirsTempFile(spillLocalDirs, "bytes-container", "", true);
    parentDir.deleteOnExit();
    tmpFile = File.createTempFile("BytesContainer", ".tmp", parentDir);
    LOG.debug("BytesContainer created temp file " + tmpFile.getAbsolutePath());
    tmpFile.deleteOnExit();

    fileOutputStream = new FileOutputStream(tmpFile);
  }
An eager bytes container that puts row bytes to an output stream.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/rowbytescontainer/VectorRowBytesContainer.java