Project Valhalla Update
summary
Project Valhalla introduces value classes (the new value modifier) and a non-nullability plan (JEP 401 starts the work) to let the JVM flatten and densify layouts, migrate Integer Optional and LocalDate to value semantics, and avoid boxing in many cases. The JVM hoists fields into registers, uses optimized calling conventions, and shows throughput gains like 3x–12x in prototypes. The roadmap includes non-nullable types and later cleanup JEPs for primitive parity and generics specialization.
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chapters (13)
- 0:00Introduction
- 0:33What is Project Valhalla
- 2:38Memory layout challenges
- 5:54The rift between types
- 10:41The life cycle of a feature
- 14:31Object identity
- 17:19Value classes
- 23:13Null restricted types
- 28:37Initialization and safety
- 34:29Tearing and atomicity
- 37:41Simplifying the model
- 44:41Future work and cleanup
- 47:18Q&A and conclusion
