The highlight package contains classes to provide "keyword in context" features typically used to highlight search terms in the text of results pages.
Packages 
Package Description
org.apache.lucene.search.highlight
Highlighting search terms.
org.apache.lucene.search.matchhighlight
This package contains several components useful to build a highlighter on top of the Matches API.
org.apache.lucene.search.uhighlight
The UnifiedHighlighter -- a flexible highlighter that can get offsets from postings, term vectors, or analysis.
org.apache.lucene.search.vectorhighlight
Another highlighter implementation based on term vectors.