Valhalla - Where Are We? #JVMLS

Presented by Brian Goetz - Java Language Architect (Java Platform Group - Oracle) during the JVM Language Summit (August 2024 - Santa Clara, CA). Project Valhalla wants to heal the rift in #Java's type system between classes and primitives by introducing value classes, which "code like a class, work like an int" and offer a flat and dense memory layout. Java's epic refactor, as it has been dubbed, has been going on for 10 years but is now entering the home stretch. At #JVMLS 2024, Java Language Architect Brian Goetz explained the proposed solution: value classes (already available in an EA build), null-restricted types, beefed up definite assignment analysis, and strict initialization. Chapters 0:00 Executive Summary 7:19 Brief History 15:26 Value Classes ⟪~⟫ Object Identity 24:03 Null-Restricted Types ⟪~⟫ Nullability 31:53 Strict Initialization 35:06 The Cascade of Simplification 40:19 Serialization 41:13 Flattening & Tearing Values 47:10 Mopping up Make sure to check the    • JVM Language Summit 2024   playlist. Resources • Project Valhalla ➤ https://openjdk.org/projects/valhalla/ • Value Classes and Objects (Preview) ➤ https://openjdk.org/jeps/401 • Valhalla Early-Access Builds Implementing Value Classes and Objects ➤ https://jdk.java.net/valhalla/ • Enhanced Primitive Boxing (Preview) ➤ https://openjdk.org/jeps/402 • Draft JEP - Null-Restricted Value Class Types (Preview) ➤ https://bugs.openjdk.org/browse/JDK-8... • Draft JEP - Null-Restricted and Nullable Types (Preview) ➤ https://bugs.openjdk.org/browse/JDK-8... • The Saga of the Parametric VM ➤ https://cr.openjdk.org/~jrose/values/... • OpenJDK ➤ https://openjdk.org • Inside Java ➤ https://inside.java/tag/valhalla • Dev.Java ➤ https://dev.java • JVMLS ➤ https://openjdk.org/projects/mlvm/jvm... Tags: #OpenJDK #Valhalla #Performance