28 April 2014, Apache Luceneā„¢ 4.8.0 available

The Lucene PMC is pleased to announce the release of Apache Lucene 4.8.0

Apache Lucene is a high-performance, full-featured text search engine
library written entirely in Java. It is a technology suitable for nearly
any application that requires full-text search, especially cross-platform.

This release contains numerous bug fixes, optimizations, and
improvements, some of which are highlighted below. The release
is available for immediate download at:

See the CHANGES.txt file included with the release for a full list of

Lucene 4.8.0 Release Highlights:

* Apache Lucene now requires Java 7 or greater (recommended is
  Oracle Java 7 or OpenJDK 7, minimum update 55; earlier versions
  have known JVM bugs affecting Lucene).

* Apache Lucene is fully compatible with Java 8.

* All index files now store end-to-end checksums, which are
  now validated during merging and reading. This ensures that
  corruptions caused by any bit-flipping hardware problems or bugs
  in the JVM can be detected earlier.  For full detection be sure
  to enable all checksums during merging (it's disabled by default).

* Lucene has a new Rescorer/QueryRescorer API to perform second-pass
  rescoring or reranking of search results using more expensive scoring
  functions after first-pass hit collection.

* AnalyzingInfixSuggester now supports near-real-time autosuggest.

* Simplified impact-sorted postings (using SortingMergePolicy and
  EarlyTerminatingCollector) to use Lucene's Sort class
  to express the sort order.

* Bulk scoring and normal iterator-based scoring were separated,
  so some queries can do bulk scoring more effectively.

* Switched to MurmurHash3 to hash terms during indexing.

* IndexWriter now supports updating of binary doc value fields.

* HunspellStemFilter now uses 10 to 100x less RAM. It also loads
  all known OpenOffice dictionaries without error.

* Lucene now also fsyncs the directory metadata on commits, if the
  operating system and file system allow it (Linux, MacOSX are
  known to work).

* Lucene now uses Java 7 file system functions under the hood,
  so index files can be deleted on Windows, even when readers are
  still open.

* A serious bug in NativeFSLockFactory was fixed, which could
  allow multiple IndexWriters to acquire the same lock.  The
  lock file is no longer deleted from the index directory
  even when the lock is not held.

* Various bugfixes and optimizations since the 4.7.2 release.

Please read CHANGES.txt for a full list of new features.

Please report any feedback to the mailing lists

Note: The Apache Software Foundation uses an extensive mirroring network
for distributing releases.  It is possible that the mirror you are using
may not have replicated the release yet.  If that is the case, please
try another mirror.  This also goes for Maven access.

Uwe Schindler
Apache Lucene PMC Chair / Committer
Bremen, Germany

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