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.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.