Review

class IndexWriter {
  /**
   * Flush all in-memory buffered updates (adds and deletes)
   * to the Directory. 
   * <p>Note: while this will force buffered docs to be
   * pushed into the index, it will not make these docs
   * visible to a reader.  Use {@link #commit()} instead
   *
   * <p><b>NOTE</b>: if this method hits an OutOfMemoryError
   * you should immediately close the writer.  See <a
   * href="#OOME">above</a> for details.</p>
   *
   * @deprecated please call {@link #commit()}) instead
   *
   * @throws CorruptIndexException if the index is corrupt
   * @throws IOException if there is a low-level IO error
   */
  public final void flush() throws CorruptIndexException, IOException {  
    if (hitOOM) {
      throw new IllegalStateException("this writer hit an OutOfMemoryError; cannot flush");
    }

    flush(true, false, true);
  }

}