As of April 7, 2008, the following is Google's position on proposals to add support for closures to Java:
Google believes Java platform will likely benefit from continued research into closures. To arrive at the best solution, Google is open to multiple parallel investigations but is not currently prepared to commit to any particular proposal. We do not expect these investigations to yield results in time for Java 7, and are of the opinion that it is premature to launch a JSR that forces us down any specific path.