Despite all bold promises from Oracle, java8 will be still much inferior to Scala:
http://www.infoq.com/articles/java-8-vs-scala (e.g. traits vs virtual methods - can't be compared)
In all of this java8 will be released no earlier than mid-2013 and scala "certainly won't be sitting still between now and 2013"(c)
(c) from comments:
"Notwithstanding the nice new features in Java 8, Scala seems (in my opinion) to remain significantly more concise and clean than Java."
"Remeber even if its java 8, it still just java. Don't expect too much."
"the Scala folks are delighted that Java 8 will have lambdas, since that will ultimately result in attention to performance of such code, and perhaps even to how it is represented in classfiles. Scala will likely benefit from the resulting improvements."