<p>Does anybody know, if closures will be in Java 7? </p>

It is unknown until the Java SE 7 JSR is created (presumably by Danny Coward) and an expert group is formed and the contents selected.
My Java 7 page is a good collection of links about Java 7 in general and has links to all of the closures proposals and blog entries:
http://tech.puredanger.com/java7#closures
And I maintain a Java 7 link blog where you can find links on closures and other stuff at:
http://java7.tumblr.com
And you might find my Java 7 Predictions blog post to be interesting as well if you want my opinions:
http://tech.puredanger.com/2008/08/02/java7-prediction-update/
UPDATE: Mark Reinhold stated at Devoxx in Dec. 08 that closures will NOT be included in Java 7 due to a lack of consensus on how to implement.