With the sequenced collections proposal, all of the new methods declared in the new interfaces have default implementations. Sequenced collections would be added to the standard edition of Java.

The Java Platform provides the most commonly used data structures in the form of the Collections Framework, and it provides a rich API to operate on them. This article explains the concepts behind ...

When Java was born, the only data structure support built into the core libraries involved arrays, vectors (essentially dynamically-sized arrays), and hash tables (for key-value pairs).