by Dan Smith on June 21, 2026

We'll review new and upcoming Java features that improve the convenience, reliability, and performance of immutable data, including:

  • Records, record patterns, and derived record creation

  • Value classes and objects

  • Early field initialization with flexible constructor bodies

  • The lazy constants API

  • Initialization diagnostics for static final fields

  • Unsafe reflective mutation or deserialization and the marshalling API as an alternative

  • In the future: immutable arrays?

We'll discuss how these features complement each other, what sorts of JVM optimizations they enable, and how to decide when they're a good fit for an application.

Make sure to check the JavaOne 2026 playlist.