Lucene 2.9.1 should hit the streets this week. 2.9.1 will be a bug fix release and includes a number of important fixes to the Lucene 2.9 release. You can see a list of the current 2.9.1 issues in JIRA here: JIRA 2.9.1 Issues. A couple of these bugs are quite nasty, so this is a highly recommended upgrade.
Why Lucene 2.9.1 rather than simply releasing the almost finished Lucene 3.0 with these bug fixes? After all, 3.0 is simply Lucene 2.9 with deprecations removed and tons of code converted to Java 1.5 (generics and what not). [though there is currently a bit of debate about adding a couple features to 3.0 as well] Well, there are two reasons. One: 2.9 was the last Java 1.4 release, and so anyone stuck on that platform would be without these fixes if we only put them in 3.0. Thats just about enough reason right there. Also though, 2: many users will not have completely moved off the deprecated API’s yet – which you will be required to do to move to 3.0. These “lazy” users will want to get these bug fixes too – without the requirement that they first finish moving to all of the new APIs. Hence Lucene 2.9.1 – coming any day now.