# Project Valhalla

Project Valhalla is augmenting the Java object model with value objects and related language and JVM features, including primitive classes and specialized generics.

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## How ParparVM Reached Performance Parity with Warmed Java 25

DevFeed: [How ParparVM Reached Performance Parity with Warmed Java 25](<https://devfeed.tech/articles/how-we-beat-hotspot-performance-by-cheating-but-not-like-that-19212.md>)

Original publisher: [Read original article](<https://www.codenameone.com/blog/beating-hotspot-performance/>)

Author: Shai Almog

Published: 2026-07-10T00:00:00Z

Content type: article

Language: en

Sources: [CodeName One](<https://devfeed.tech/sources/codename-one.md>)

Topics: [Java](<https://devfeed.tech/topics/java.md>), [Benchmark](<https://devfeed.tech/topics/benchmark.md>), [Optimization](<https://devfeed.tech/topics/optimization.md>), [Code generation](<https://devfeed.tech/topics/code-generation.md>), [C](<https://devfeed.tech/topics/c.md>), [Project Valhalla](<https://devfeed.tech/topics/project-valhalla.md>)

Tags: [benchmark](<https://devfeed.tech/tags/benchmark.md>), [c](<https://devfeed.tech/tags/c.md>), [java](<https://devfeed.tech/tags/java.md>), [memory](<https://devfeed.tech/tags/memory.md>), [optimization](<https://devfeed.tech/tags/optimization.md>), [performance](<https://devfeed.tech/tags/performance.md>), [project-valhalla](<https://devfeed.tech/tags/project-valhalla.md>)

### AI overview

This article explains how ParparVM, an ahead-of-time virtual machine that compiles Java bytecode to C, improved from 4.21x slower than warmed Java 25 to geometric-mean parity across ten benchmarks. It describes changes involving heap layout, code generation, allocation, and collection, with correctness checked against HotSpot.

### Source excerpt

ParparVM went from 4.21x slower than warmed Java 25 to geomean parity, with peak memory below the JVM's. The architecture behind it, in C terms.

## iOS Density, Scroll Physics, and Accessibility

DevFeed: [iOS Density, Scroll Physics, and Accessibility](<https://devfeed.tech/articles/ios-density-scroll-physics-and-accessibility-19339.md>)

Original publisher: [Read original article](<https://www.codenameone.com/blog/ios-density-scroll-and-accessibility/>)

Author: Shai Almog

Published: 2026-04-24T00:00:00Z

Content type: article

Language: en

Sources: [CodeName One](<https://devfeed.tech/sources/codename-one.md>)

Topics: [iOS](<https://devfeed.tech/topics/ios.md>), [Java](<https://devfeed.tech/topics/java.md>), [Project Valhalla](<https://devfeed.tech/topics/project-valhalla.md>), [Accessibility](<https://devfeed.tech/topics/accessibility.md>)

Tags: [accessibility](<https://devfeed.tech/tags/accessibility.md>), [ios](<https://devfeed.tech/tags/ios.md>), [java](<https://devfeed.tech/tags/java.md>), [project-valhalla](<https://devfeed.tech/tags/project-valhalla.md>), [valhalla](<https://devfeed.tech/tags/valhalla.md>)

### AI overview

This Codename One update explains that its iOS pixel-density lookup table omitted several newer iPhone models, causing inaccurate physical-unit rendering. The table and unknown-device fallback were updated, and the article also discusses iOS performance work related to Java, Project Valhalla, and the Vector API.

### Source excerpt

If you have shipped to an iPhone 14 Pro or anything newer, your density calculations have been wrong until this week. Also in this update, Codename One delivers the performance benefits that Java developers are still waiting on from the Vector API and Project Valhalla -- available today, and already making our Base64 on iOS faster than Apple's own.

## KotlinConf 2025 Recordings

DevFeed: [KotlinConf 2025 Recordings](<https://devfeed.tech/articles/kotlinconf-2025-recordings-39350.md>)

Original publisher: [Read original article](<https://kt.academy/article/kotlinconf2025-recordings>)

Published: 2025-07-01T00:00:00Z

Content type: article

Language: en

Sources: [Kt. Academy](<https://devfeed.tech/sources/kt-academy.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [recommendations](<https://devfeed.tech/topics/recommendations.md>), [Compiler](<https://devfeed.tech/topics/compiler.md>), [Project Valhalla](<https://devfeed.tech/topics/project-valhalla.md>), [Coroutines](<https://devfeed.tech/topics/coroutines.md>), [debugging](<https://devfeed.tech/topics/debugging.md>)

Tags: [2025](<https://devfeed.tech/tags/2025.md>), [compiler](<https://devfeed.tech/tags/compiler.md>), [coroutines](<https://devfeed.tech/tags/coroutines.md>), [debugging](<https://devfeed.tech/tags/debugging.md>), [kotlinconf](<https://devfeed.tech/tags/kotlinconf.md>), [project-valhalla](<https://devfeed.tech/tags/project-valhalla.md>), [recommendations](<https://devfeed.tech/tags/recommendations.md>), [workshop-learning-programming](<https://devfeed.tech/tags/workshop-learning-programming.md>), [writing](<https://devfeed.tech/tags/writing.md>)

### AI overview

An opinionated list of recommended recordings from KotlinConf 2025, including the keynote, Rich Errors in Kotlin, compiler plugins, Project Valhalla, and debugging and performance tuning in a coroutine world.

### Source excerpt

My list of must-watch from KotlinConf 2025.