以下列出的变化是针对上个版本1.9.1以来的，DLOG4J将随即更新为该最新版本

API Changes

1. All deprecated methods and fields have been removed, except
    DateField, which will still be supported for some time
    so Lucene can read its date fields from old indexes
    (Yonik Seeley & Grant Ingersoll)

2. DisjunctionSumScorer is no longer public.
    (Paul Elschot via Otis Gospodnetic)
   
3. Creating a Field with both an empty name and an empty value
    now throws an IllegalArgumentException
    (Daniel Naber)

New features

1. LUCENE-496: Command line tool for modifying the field norms of an
    existing index; added to contrib/miscellaneous.  (Chris Hostetter)

2. LUCENE-577: SweetSpotSimilarity added to contrib/miscellaneous.
    (Chris Hostetter)
   
Bug fixes

1. LUCENE-330: Fix issue of FilteredQuery not working properly within
    BooleanQuery.  (Paul Elschot via Erik Hatcher)

2. LUCENE-515: Make ConstantScoreRangeQuery and ConstantScoreQuery work
    with RemoteSearchable.  (Philippe Laflamme via Yonik Seeley)

3. Added methods to get/set writeLockTimeout and commitLockTimeout in
    IndexWriter. These could be set in Lucene 1.4 using a system property.
    This feature had been removed without adding the corresponding
    getter/setter methods.  (Daniel Naber)

4. LUCENE-413: Fixed ArrayIndexOutOfBoundsException exceptions
    when using SpanQueries. (Paul Elschot via Yonik Seeley)

5. Implemented FilterIndexReader.getVersion() and isCurrent()
    (Yonik Seeley)

6. LUCENE-540: Fixed a bug with IndexWriter.addIndexes(Directory[])
    that sometimes caused the index order of documents to change.
    (Yonik Seeley)

7. LUCENE-526: Fixed a bug in FieldSortedHitQueue that caused
    subsequent String sorts with different locales to sort identically.
    (Paul Cowan via Yonik Seeley)

8. LUCENE-541: Add missing extractTerms() to DisjunctionMaxQuery
    (Stefan Will via Yonik Seeley)

9. LUCENE-514: Added getTermArrays() and extractTerms() to
    MultiPhraseQuery (Eric Jain & Yonik Seeley)

10. LUCENE-512: Fixed ClassCastException in ParallelReader.getTermFreqVectors
    (frederic via Yonik)

11. LUCENE-352: Fixed bug in SpanNotQuery that manifested as
    NullPointerException when "exclude" query was not a SpanTermQuery.
    (Chris Hostetter)

12. LUCENE-572: Fixed bug in SpanNotQuery hashCode, was ignoring exclude clause
    (Chris Hostetter)

13. LUCENE-561: Fixed some ParallelReader bugs. NullPointerException if the reader
    didn't know about the field yet, reader didn't keep track if it had deletions,
    and deleteDocument calls could circumvent synchronization on the subreaders.
    (Chuck Williams via Yonik Seeley)

14. LUCENE-556: Added empty extractTerms() implementation to MatchAllDocsQuery and
    ConstantScoreQuery in order to allow their use with a MultiSearcher.
    (Yonik Seeley)

15. LUCENE-546: Removed 2GB file size limitations for RAMDirectory.
    (Peter Royal, Michael Chan, Yonik Seeley)

16. LUCENE-485: Don't hold commit lock while removing obsolete index
    files.  (Luc Vanlerberghe via cutting)