Release a 16 KB page aligned version

[GrahamBorland]

Soon, native libraries for Android will have to be aligned on 16 KB page boundaries. This requires the library to be recompiled with updated settings.

Running the check_elf_alignment.sh script from that Android Developer page shows this:

armeabi-v7a/libj2v8.so: UNALIGNED (2**12)
x86/libj2v8.so: UNALIGNED (2**12)
arm64-v8a/libj2v8.so: ALIGNED (2**16)
x86_64/libj2v8.so: UNALIGNED (2**12)

Please release a new build of J2V8 which is suitable for the upcoming 16 KB page size environments.

Thank you!

[GrahamBorland]

My understanding is that there is a hard deadline of 1st November 2025 for this.

Based on previous years, I expect that by 2025-08-31 all new/updated apps will be required to target API level 35 (source).

Following from that, apps targeting API level 35 will be required to comply with 16 KB page alignment by 2025-11-01 (source):

Starting November 1st, 2025, all new apps and updates to existing apps submitted to Google Play and targeting Android 15+ devices must support 16 KB page sizes.

[GrahamBorland]

We have a fork with a 16Kb aligned version of the latest 6.2.1 release for Android.

https://github.com/ynab/J2V8/releases/tag/6.2.1-16kb.2

maven { url = "https://jitpack.io" }
implementation("com.github.ynab:j2v8:6.2.1-16kb.2")

[phanendharreddy]

Hi @GrahamBorland,
I've submitted a pull request that addresses the 16 KB page alignment requirement for Android builds: PR #607.
This update adds the necessary linker flags to both the CMake and Android.mk build scripts, ensuring all generated ELF binaries are aligned to 16 KB as required for Android 15+ (API level 35+).
I've rebuilt and verified the native libraries for all ABIs using the recommended alignment check script.
Please let me know if any further changes or testing are needed! Thank you very much!

[GrahamBorland]

@phanendharreddy I'm not one of the J2V8 maintainers so I can't do anything with your PR, but thanks. 😄

[phanendharreddy]

Thanks for your response, @GrahamBorland ! I’ll wait to hear back from the maintainers about the pull request update.

[cdiazc]

Thanks for opening this @GrahamBorland and for the proposed fix @phanendharreddy . I'm in the same position, J2V8 is the only dependency on my project not 16KB aligned. Let's hope the maintainers will accept it !

[GrahamBorland]

@cdiazc @phanendharreddy just in case you missed my earlier comment, we do have a working fork here:

We have a fork with a 16Kb aligned version of the latest 6.2.1 release for Android.

https://github.com/ynab/J2V8/releases/tag/6.2.1-16kb.2

maven { url = "https://jitpack.io" }
implementation("com.github.ynab:j2v8:6.2.1-16kb.2")

[cdiazc]

@cdiazc @phanendharreddy just in case you missed my earlier comment, we do have a working fork here:

We have a fork with a 16Kb aligned version of the latest 6.2.1 release for Android.
https://github.com/ynab/J2V8/releases/tag/6.2.1-16kb.2

maven { url = "https://jitpack.io" }
implementation("com.github.ynab:j2v8:6.2.1-16kb.2")

Thanks @GrahamBorland ! I did try it and works like a charm, great contribution !
I feel it is still worth pushing for the official repo to fix/release this, don't you think ?

[GrahamBorland]

Yes, but they won't. The repo has been abandoned for years.

[steverichey]

Thanks for raising this @GrahamBorland, and for the fork. Do you have any insight into why check_elf_alignment.sh reports ALIGNED for the arm64-v8a binary? That's supposed to be the only binary that matters, but devices enforcing the 16KB alignment definitely report the binary is 4KB aligned at runtime.

[GrahamBorland]

I have no idea, I'm afraid! I didn't dig into it in much detail.

[k4k7us23]

I have just built a fork with 16kb page size alignment and V8's version updated to 13.9.205.21. Updated V8 engine works way faster than 9.3.345.11, which is used in the main repo’s latest version. Feel free to try the fork and provide feedback.

https://github.com/k4k7us23/J2V8

dependencies {
    implementation 'io.github.k4k7us23:j2v8:1.0'
}

[whoozle]

@k4k7us23 your build can't load native library on android API 28 (easy reproducible in emulator), with unknown reloc type 35 error 😢
@GrahamBorland build works totally fine but I guess it still uses old v8