What do you need that:

   http://lucene.apache.org/java/docs/demo.html

plus the source of the demo applications:

   <lucene>/src/demo/org/apache/lucene/demo/IndexFiles.java
   <lucene>/src/demo/org/apache/lucene/demo/SearchFiles.java

doesn't give you ?

(Replace <lucene> in the above by the location where you've unpacked the
downloaded source, or replace it with:
   http://svn.apache.org/viewcvs.cgi/lucene/java/trunk/
to find it on the Web.)

   -- chris