The Collections Framework has been around for a long time. The existing implementations have mostly served us well, but there's still room for improvement. Current work slated for Java 9 includes new collection implementations that add convenience, immutability, and space efficiency. The "API footprint" of the new collections will be extremely small, making them simple to learn and use. The new collections implement the standard collections interfaces, so they will be readily interoperable with code that uses the collections framework. The benefits will be simpler, cleaner code, and reduced memory consumption for many common cases.