Adam Retter

adam@evolvedbinary.com
 

RocksDB Meetup
@ Meta, Menlo Park
2026-03-16

@adamretter

• Evolved Binary

  • UK - Software, Consultancy, Training, and R&D

  • Contributors to RocksJava for > 10 Years

• RocksJava (Java, C++, and JNI / FFM)

  • Ensure Feature Parity with C++ API

  • Performance Improvements

  • Docker Images - Build Environments - CentOS 7 / Alpine 3.20

  • Build and Release RockJava binaries (135 releases since 2016)

• Helped Porting RocksDB

  • Windows / macOS / z/OS / PPC / Arm64 / RISC-V

• GitHub issues, and general bug-fixing

• Intentionally Conservative!

  • Java 8 (2014)

• Targets 14 platforms:

  • Linux

    • i386 / amd64 / ppc64le / aarch64 / s390x / RISC-V

    • GNU libc 2.17 (2012)

    • musl Libc 1.2.5 (2024)

  • Windows (Windows 10+ / Windows Server 2016+)

    • amd64

    • vcruntime140.dll and UCRT

  • macOS (Mojave 10.14 +)

    • amd64

    • aarch64

• Upcoming targets:

  • Windows aarch64

  • AIX PPC64

  • z/OS

  • FreeBSD amd64

  • OpenBSD amd64

• Cloud Hardware Donations (Thank You!):

  • Evolved Binary - RISC-V, macOS, Windows, Linux amd64/i386, FreeBSD, OpenBSD

  • Oregon State University - Open Source Labs - ppc64le Linux, ppc64 AIX

  • Huawei - aarch64 Linux

  • Marist University - s390x Linux

  • IBM - z/OS

• Driven from macOS

  • We can't emulate/virtualize macOS

  • Can no longer build Linux i386 binaries under macOS (on Apple Silicon)

    • https://github.com/bell-sw/Liberica/issues/227

• RocksJava upgrade to C++ 20 was challenging

  • We want to target older GNU/MUSL libc, or Windows, or macOS

  • Need C++ 20 compiler that supports older platform

  • Thank you SCL for CentOS!

• Maven Central changed its publication process

  • Now hard to publish without Apache Maven

• RocksJava is currently built using JNI (Java Native Interface)

• Java FFM (Foreign Function and Memory API)

  • Modern replacement for JNI

  • Previewed in Java 18 (Mar. 2022)

  • Stabilised in Java 22 (Mar. 2024)

  • Performance improved in Java 24 (Mar. 2025)

• Advantages

  • Less/No binding code (delete JNI C++ code)

  • Performance?

• Disadvantages

  • Need to improve RocksDB C API (Advantage?)

  • Requires dependent projects to upgrade their Java (>= RocksJava)

• Java JNI and FFM Benchmarks (JMH)
  https://github.com/evolvedbinary/jni-benchmarks

• RocksDB Blog - Java API Performance Enhancements
  https://rocksdb.org/blog/2023/11/06/java-jni-benchmarks.html

• RocksDB Blog - Java Foreign Function Interface
  https://rocksdb.org/blog/2024/02/20/foreign-function-interface.html

• We need:

  • Improved RocksDB C API (Feature Partity, etc.)

    • We can do that!

• Possible Approaches

  • Big Bang - Replace JNI with FFM

    • Some aspects of JNI may not be replaceable!

  • Phased

    • Gradually replace parts of JNI with FFM

  • Parallel

    • Develop FFM in Parallel to JNI (Support both newer and older Java versions)

    • Deprecate JNI

    • Grow FFM Adoption

    • Remove JNI

• No plans to remove JNI from Java at present

  • New Projects are recommended to use FFM over JNI

• RocksDB is widely used as infrastructure:

  • e.g. Many Apache projects use RocksJava

  • Java Binaries are Forwards Compatible - Not Backwards Compatible

  • RocksJava's use of Java 8 (and older glibc, etc.) ensures wide compatibility

• Incorporating Java FFM means:

  • Moving to at least Java 22 (Mar. 2024) as a minimum

  • Closest LTS release is Java 25 (Sept. 2025)