: I noticed that apache solr 4.2 uses the lucene codec 4.1. How can I : switch to 4.2?
Unless you've configured something oddly, Solr is already using the 4.2 codec. What you are probably seeing is that the fileformat for several types of files hasn't changed from the 4.1 (or even 4.0) versions, so they are still used in 4.2 (and confusingly include "Lucene41" in the filenames in several cases). Note that in the 4.2 codec package javadocs, several codec related classes are not implemented, and the docs link back to the 4.1 and 4.0 implementations... https://lucene.apache.org/core/4_2_0/core/org/apache/lucene/codecs/lucene42/package-summary.html If you peek inside the Lucene42Codec class you'll also see... private final StoredFieldsFormat fieldsFormat = new Lucene41StoredFieldsFormat(); private final TermVectorsFormat vectorsFormat = new Lucene42TermVectorsFormat(); private final FieldInfosFormat fieldInfosFormat = new Lucene42FieldInfosFormat(); private final SegmentInfoFormat infosFormat = new Lucene40SegmentInfoFormat(); private final LiveDocsFormat liveDocsFormat = new Lucene40LiveDocsFormat(); -Hoss