Two OpenJDK draft proposals would enhance the expressiveness of pattern matching in Java and boost data-oriented queries, potentially previewing in Java 17.

Java SE 14 (March 2020) introduced a limited form of pattern matching as a preview feature, which becomes a permanent feature in Java SE 16 (March 2021).

The Observable design pattern is found in many Java APIs and in reactive programming. Here's an introduction to the timeless Observable pattern in Java.