The old Lucene query parser used to have only one class that performed all the parsing operations. In the new query parser structure, the parsing was divided in 3 steps: parsing (syntax), processing (semantic) and building.
The classes contained in the package org.apache.lucene.queryParser.standard are used to reproduce the same behavior as the old query parser.
Check {@link org.apache.lucene.queryparser.flexible.standard.StandardQueryParser} to quick start using the Lucene query parser.