Java 25に至る道

2026.01.10 Burikaigi 2026 発表資料

Transcript

1. Java 25 に至る道 Java in the Box カサレアル 櫻庭 祐一
2. Agenda Java のつくり方 JEP Java の方向性と新機能 まとめ
3. Javaのつくり方 Mark Reinhold
4. のつくり方 Java OpenJDK - JDK Project のプロジェクトをまとめて OpenJDK JDK を作成 半年ごとの定期リリース できたものからリリース Java 25: 2025/09/16 Java 26: 2026/03/17 LTS はディストリビュータが決める Oracle, Red Hat は2年周期 LTS: 11, 17, 21, 25...
5. OpenJDK Group Compiler HotSpot Core Libs et al. Project sponsored Amber Valhalla Leyden et al. JEP proposed proposed JDK Enhancement Proposal
6. JEP
7. JEP: JDK Enhancement Proposal JDK に対する機能提案 新機能だけでなく、 機能の削除も お試し機能と正式な機能 Preview JEP Incubator JEP Experimental JEP 言語仕様 コアライブラリ VM コアライブラリ以外のAPI Standard JEP 正式機能
8. JEP: JDK Enhancement Proposal JDK に対する機能提案 新機能だけでなく、 機能の削除も お試し機能と正式な機能 Preview JEP Incubator JEP Experimental JEP 言語仕様 コアライブラリ VM コアライブラリ以外のAPI Standard JEP 正式機能
9. Java 22 423: Region Pinning for G1 454: Foreign Function & Memory API 456: Unnamed Variables & Patterns 458: Launch Multi-File Source-Code Programs Java 23 467: Markdown Documentation Comments 471: Deprecate the Memory-Access Methods in sun.misc.Unsafe for Removal 474: ZGC: Generational Mode by Default Java 24 472: Prepare to Restrict the Use of JNI 475: Late Barrier Expansion for G1 479: Remove the Windows 32-bit x86 Port 483: Ahead-of-Time Class Loading & Linking 484: Class-File API 485: Stream Gatherers 486: Permanently Disable the Security Manager 490: ZGC: Remove the Non-Generational Mode 491: Synchronize Virtual Threads without Pinning 493: Linking Run-Time Images without JMODs 496: Quantum-Resistant Module-Lattice-Based Key Encapsulation Mechanism 497: Quantum-Resistant Module-Lattice-Based Digital Signature Algorithm 498: Warn upon Use of Memory-Access Methods in sun.misc.Unsafe 501: Deprecate the 32-bit x86 Port for Removal Java 25 470: PEM Encodings of Cryptographic Objects (Preview) 502: Stable Values (Preview) 503: Remove the 32-bit x86 Port 505: Structured Concurrency (Fifth Preview) 506: Scoped Values 507: Primitive Types in Patterns, instanceof, and switch (Third Preview) 508: Vector API (Tenth Incubator) 509: JFR CPU-Time Pro ling (Experimental) 510: Key Derivation Function API 511: Module Import Declarations 512: Compact Source Files and Instance Main Methods 513: Flexible Constructor Bodies 514: Ahead-of-Time Command-Line Ergonomics 515: Ahead-of-Time Method Pro ling 518: JFR Cooperative Sampling 519: Compact Object Headers 520: JFR Method Timing & Tracing 521: Generational Shenandoah Java 22, 23, 24 は Standard JEP のみ
10. Java 22 423: Region Pinning for G1 454: Foreign Function & Memory API 456: Unnamed Variables & Patterns 458: Launch Multi-File Source-Code Programs Java 23 467: Markdown Documentation Comments 471: Deprecate the Memory-Access Methods in sun.misc.Unsafe for Removal 474: ZGC: Generational Mode by Default Java 24 472: Prepare to Restrict the Use of JNI 475: Late Barrier Expansion for G1 479: Remove the Windows 32-bit x86 Port 483: Ahead-of-Time Class Loading & Linking 484: Class-File API 485: Stream Gatherers 486: Permanently Disable the Security Manager 490: ZGC: Remove the Non-Generational Mode 491: Synchronize Virtual Threads without Pinning 493: Linking Run-Time Images without JMODs 496: Quantum-Resistant Module-Lattice-Based Key Encapsulation Mechanism 497: Quantum-Resistant Module-Lattice-Based Digital Signature Algorithm 498: Warn upon Use of Memory-Access Methods in sun.misc.Unsafe 501: Deprecate the 32-bit x86 Port for Removal Java 25 470: PEM Encodings of Cryptographic Objects (Preview) 502: Stable Values (Preview) 503: Remove the 32-bit x86 Port 505: Structured Concurrency (Fifth Preview) 506: Scoped Values 507: Primitive Types in Patterns, instanceof, and switch (Third Preview) 508: Vector API (Tenth Incubator) 509: JFR CPU-Time Pro ling (Experimental) 510: Key Derivation Function API 511: Module Import Declarations 512: Compact Source Files and Instance Main Methods 513: Flexible Constructor Bodies 514: Ahead-of-Time Command-Line Ergonomics 515: Ahead-of-Time Method Pro ling 518: JFR Cooperative Sampling 519: Compact Object Headers 520: JFR Method Timing & Tracing 521: Generational Shenandoah Java 22, 23, 24 は Standard JEP のみ 宣言的記法 小さなオブジェクト 初心者に優しく 起動時間短縮 Safety/Integrity
11. Java 22 423: Region Pinning for G1 454: Foreign Function & Memory API 456: Unnamed Variables & Patterns 458: Launch Multi-File Source-Code Programs Java 23 467: Markdown Documentation Comments 471: Deprecate the Memory-Access Methods in sun.misc.Unsafe for Removal 474: ZGC: Generational Mode by Default Java 24 472: Prepare to Restrict the Use of JNI 475: Late Barrier Expansion for G1 479: Remove the Windows 32-bit x86 Port 483: Ahead-of-Time Class Loading & Linking 484: Class-File API 485: Stream Gatherers 486: Permanently Disable the Security Manager 490: ZGC: Remove the Non-Generational Mode 491: Synchronize Virtual Threads without Pinning 493: Linking Run-Time Images without JMODs 496: Quantum-Resistant Module-Lattice-Based Key Encapsulation Mechanism 497: Quantum-Resistant Module-Lattice-Based Digital Signature Algorithm 498: Warn upon Use of Memory-Access Methods in sun.misc.Unsafe 501: Deprecate the 32-bit x86 Port for Removal Java 25 470: PEM Encodings of Cryptographic Objects (Preview) 502: Stable Values (Preview) 503: Remove the 32-bit x86 Port 505: Structured Concurrency (Fifth Preview) 506: Scoped Values 507: Primitive Types in Patterns, instanceof, and switch (Third Preview) 508: Vector API (Tenth Incubator) 509: JFR CPU-Time Pro ling (Experimental) 510: Key Derivation Function API 511: Module Import Declarations 512: Compact Source Files and Instance Main Methods 513: Flexible Constructor Bodies 514: Ahead-of-Time Command-Line Ergonomics 515: Ahead-of-Time Method Pro ling 518: JFR Cooperative Sampling 519: Compact Object Headers 520: JFR Method Timing & Tracing 521: Generational Shenandoah 宣言的記法 小さなオブジェクト 初心者に優しく 起動時間短縮 Safety/Integrity Java 22 423: Region Pinning for G1 454: Foreign Function & Memory API 456: Unnamed Variables & Patterns 458: Launch Multi-File Source-Code Programs Java 23 467: Markdown Documentation Comments 471: Deprecate the Memory-Access Methods in sun.misc.Unsafe for Removal 474: ZGC: Generational Mode by Default Java 24 472: Prepare to Restrict the Use of JNI 475: Late Barrier Expansion for G1 479: Remove the Windows 32-bit x86 Port 483: Ahead-of-Time Class Loading & Linking 484: Class-File API 485: Stream Gatherers 486: Permanently Disable the Security Manager 490: ZGC: Remove the Non-Generational Mode 491: Synchronize Virtual Threads without Pinning 493: Linking Run-Time Images without JMODs 496: Quantum-Resistant Module-Lattice-Based Key Encapsulation Mechanism 497: Quantum-Resistant Module-Lattice-Based Digital Signature Algorithm 498: Warn upon Use of Memory-Access Methods in sun.misc.Unsafe 501: Deprecate the 32-bit x86 Port for Removal Java 25 470: PEM Encodings of Cryptographic Objects (Preview) 502: Stable Values (Preview) 503: Remove the 32-bit x86 Port 505: Structured Concurrency (Fifth Preview) 506: Scoped Values 507: Primitive Types in Patterns, instanceof, and switch (Third Preview) 508: Vector API (Tenth Incubator) 509: JFR CPU-Time Pro ling (Experimental) 510: Key Derivation Function API 511: Module Import Declarations 512: Compact Source Files and Instance Main Methods 513: Flexible Constructor Bodies 514: Ahead-of-Time Command-Line Ergonomics 515: Ahead-of-Time Method Pro ling 518: JFR Cooperative Sampling 519: Compact Object Headers 520: JFR Method Timing & Tracing 521: Generational Shenandoah
12. Javaの方向性と新機能 Brian Goetz
13. Javaの方向性 宣言的記法 小さなオブジェクト 初心者に優しく 起動時間短縮 Safety/Integrity
14. 初心者に優しく Gavin Bierman Javaは初心者にとってハードルが高い？ お約束事が多い 説明の難しい概念が ... 実行までの道のりが長い JEP 458: Launch Multi-File Source-Code Programs JEP 511: Module Import Declarations JEP 512: Compact Source Files and Instance Main Methods
15. Hello, World! Hello.java public class Hello { public static void main(String... args) { System.out.println("Hello, World!")); } } ? void main() { IO.println("Hello, World!")); } クラス不要 メソッド簡略化 標準入出力クラス main
16. 宣言的記法 ・ 小さなオブジェクト Brian Goetz Java 8: Project Lambdaからの流れ 文から式へ 少数のミュータブルな大きいオブジェクトから 多数のイミュータブルな小さいオブジェクトへ 手続き型から宣言型へ JEP 485: Stream Gatherers JEP 513: Flexible Constructor Bodies JEP 519: Compact Object Headers JEP 401: Value Classes and Objects 導入時期未定
17. Stream Gatherer Stream API の中間操作の拡充 中間操作で状態を保持可能 のような動作が可能 Collector map Source lter collect
18. Stream Gatherer Stream API の中間操作の拡充 中間操作で状態を保持可能 のような動作が可能 Collector Source lter gather collect
19. Stream Gatherer Stream API の中間操作の拡充 中間操作で状態を保持可能 のような動作が可能 Collector List<Double> nums = ...; List<Double> movingAves = nums.stream() .gather(Gatherers.windowSliding(3)) .map(f -> f.stream() .collect(Collectors.averagingDouble(x -> x))) .toList(); 例 : 移動平均 3データをまとめる
20. Compact Object Header Roman Kennke Compact Object Header - Project Lilliput ヒープでのオブジェクトヘッダーのサイズがあなどれない record Point( double x, double y ) {} Header double double 128bit (16byte) 64bit (8byte) 64bit (8byte) 未使用ビットの見直しなどで 64bit 64bit (8byte) 128bit
21. 起動時間短縮 Mark Reinhold - Project Leyden コンテナ サーバーレス 実行環境の変化 起動時間がボトルネック Project Leyden 起動時間短縮 ピークパフォーマンスに至る時間短縮 フットプリント削減
22. 起動時間短縮 - Project Leyden JEP 483: Ahead-of-Time Class Loading & Linking JEP 514: Ahead-of-Time Command-Line Ergonomics JEP 515: Ahead-of-Time Method Pro ling クラスロード後のイメージをキャッシュ化 プロファイリング結果をキャッシュ化 JEP Draft: Ahead-of-Time Code Compilation ネイティブイメージ作成 導入時期未定
23. Safety / Integrity 安全性の追及は常に セキュリティ関連 API ポスト量子暗号の対応など 保守できない機能の削除 ポーティング削除など 32bit WIndows 安全に使うためのデフォルト動作の変更 使用時に警告 今後は原則禁止 JNI Ron Pressler やリフレクションなども FMM
24. まとめ JEPを追うことで方向性が分かる 今、力を入れているところ これから向かおうとしているところ 時代が変われば、プログラミングスタイルも変わる 手続き型から宣言型 ミュータブルからイミュータブル
25. Reference OpenJDK JDK Project https://openjdk.org/projects/jdk/ JEP https://openjdk.org/projects/valhalla/ Project Valhalla https://openjdk.org/jeps/0 Project Lilliput Wiki https://wiki.openjdk.org/spaces/lilliput/overview YouTube: JVM Language Summit 2025 https://youtube.com/playlist?list=PLX8CzqL3ArzUOgZpIX6GsoRhPbnij-sco Project Leyden https://openjdk.org/projects/leyden/