A Peek Past Lambda
Brian Goetz (via Dave Dribin):
It is my belief that the best direction for evolving Java is to encourage a more functional style of programming. The role of Lambda is primarily to support the development and consumption of more functional-like libraries; I've offered examples such as filter-map-reduce to illustrate this direction.
There is plenty of evidence in the ecosystem to support the hypothesis that, if given the tools to do so easily, object-oriented programmers are ready to embrace functional techniques (such as immutability) and work them into an object-oriented view of the world, and will write better, less error-prone code as a result.