I use Hibernate search for full text search in my web application. I have button for index creation in admin panel. I do it by this code:

fullTextSession.createIndexer()
.purgeAllOnStart(true)
.optimizeAfterPurge(true)
.optimizeOnFinish(true)
.batchSizeToLoadObjects( 25 )
.threadsToLoadObjects( 5 )
.threadsForSubsequentFetching( 20 )
.startAndWait();

If index was build correctly and then I push this button again old index files still on disk and program creates new index. And so on. Can you help me remove old index files before creating new?

What do you mean that a new index gets created? Are there duplicate files? Or duplicate search results? purgeAllOnStart will not physically delete the existing index, but rather first mark the existing documents for deletion and then re-index. On the other hand optimize should be called when the processing is finished.
Maybe you could specify a little more what you mean.

--Hardy