5 ms·

> J2Cl which translates Java to Javascript Oh that's sure an interesting project. A shame it apparently requires the use of Bazel as the build system. I wish I

> J2Cl which translates Java to Javascript Oh that's sure an interesting project. A shame it apparently requires the use of Bazel as the build system. I wish I could just add it as a module to my existing Maven project and rewrite my frontend code from TypeScript to Java — but that's Google, and Google can never stop inventing their own ways of building things. edit: I might try https://github.com/Vertispan/j2clmavenplugin https://github.com/Vertispan/j2clmavenplugin

passerby1 5y ago
I've never used bazel before. Is it that bad?
- kaba0 5y ago
  As far as I know it’s not necessarily bad, it’s just not standard, especially not for java projects, so it may require strange file hierarchies.
  - lbhdc 5y ago
    Bazel doesn't enforce a structure. Bazel makes you add WORKSPACE and BUILD files throughout your project to describe your targets and their dependencies.
- grishka 5y ago
  Doesn't matter whether it's good or bad, I already have an existing Maven project I would like to try this in. Besides, Maven and Gradle are simply what I'm used to when working with Java projects. Yet another build system is about the last thing I need. I consider building Java to be a fully solved problem.
- lbhdc 5y ago
  I use it in a few projects, all are polyglot monorepos. I think bazel really shines in that setting. I have one tool to interact with my codebase. I use it to manage all build, test, and deploy, but also code generation, running local dev servers. I think its worth the hassle of setting it up for large multi language projects.
tannhaeuser 5y ago
There are third-party maven and gradle integrations and plugins at various stages. And you can also run bazel -s to log the exact commands it is running (basically j2cl with annotation processing plus closure-compiler). Though extracting good pairings of j2cl, closure-compiler, gwt and jre-emul libs etc tends to become a pointless chore with j2cl, closure-compiler being updated all the time without documented releases other than timestamps. Last I checked, closure-compiler was at a 2020ish rev in a recent j2cl bazel build checkout only slightly newer than the initial 2019 release, with j2cl apparently focussing on kotlin and also an experimental wasm target requiring wasmgc hence Chrome. It's a pity Google doesn't anymore see value in external input/testing for j2cl and closure-compiler since these are decent projects.
TeaVMFan 5y ago
TeaVM converts Java to JS, and it has first-class maven support. https://teavm.org https://teavm.org
- kaba0 5y ago
  It runs byte code in a JS-(or WASM) implemented JVM, isn’t it? It is really fast, but slightly different than J2CL.
  - TeaVMFan 5y ago
    TeaVM transpiles Java bytecode to native JS, only keeping the required classes. The output is compact, efficient, and fast to download in a browser. No interpreter or runtime is used, which makes TeaVM apps fast and light.
    - kaba0 5y ago
      Oh I see. The difference is that it works from class files, not source (making other jvm languages supported as well)
niloc132 5y ago
We are mostly targeting enabling GWT applications to be able to (relatively seamlessly) update to J2CL as a compiler, but are definitely interested in apps or libraries starting their lives as a plain Java project and expose it to JS/TS/closure in a variety of ways. Aside from the github repo, most of the conversation as we work on this happens at https://gitter.im/vertispan/j2cl https://gitter.im/vertispan/j2cl - feel free to stop by to ask any questions or share a use case that seems under-represented.

passerby1 5y ago

I've never used bazel before. Is it that bad?

kaba0 5y ago
As far as I know it’s not necessarily bad, it’s just not standard, especially not for java projects, so it may require strange file hierarchies.
- lbhdc 5y ago
  Bazel doesn't enforce a structure. Bazel makes you add WORKSPACE and BUILD files throughout your project to describe your targets and their dependencies.
grishka 5y ago
Doesn't matter whether it's good or bad, I already have an existing Maven project I would like to try this in. Besides, Maven and Gradle are simply what I'm used to when working with Java projects. Yet another build system is about the last thing I need. I consider building Java to be a fully solved problem.
lbhdc 5y ago
I use it in a few projects, all are polyglot monorepos. I think bazel really shines in that setting. I have one tool to interact with my codebase. I use it to manage all build, test, and deploy, but also code generation, running local dev servers. I think its worth the hassle of setting it up for large multi language projects.

tannhaeuser 5y ago

There are third-party maven and gradle integrations and plugins at various stages. And you can also run bazel -s to log the exact commands it is running (basically j2cl with annotation processing plus closure-compiler). Though extracting good pairings of j2cl, closure-compiler, gwt and jre-emul libs etc tends to become a pointless chore with j2cl, closure-compiler being updated all the time without documented releases other than timestamps. Last I checked, closure-compiler was at a 2020ish rev in a recent j2cl bazel build checkout only slightly newer than the initial 2019 release, with j2cl apparently focussing on kotlin and also an experimental wasm target requiring wasmgc hence Chrome. It's a pity Google doesn't anymore see value in external input/testing for j2cl and closure-compiler since these are decent projects.

TeaVMFan 5y ago

TeaVM converts Java to JS, and it has first-class maven support. https://teavm.org https://teavm.org

kaba0 5y ago
It runs byte code in a JS-(or WASM) implemented JVM, isn’t it? It is really fast, but slightly different than J2CL.
- TeaVMFan 5y ago
  TeaVM transpiles Java bytecode to native JS, only keeping the required classes. The output is compact, efficient, and fast to download in a browser. No interpreter or runtime is used, which makes TeaVM apps fast and light.
  - kaba0 5y ago
    Oh I see. The difference is that it works from class files, not source (making other jvm languages supported as well)

niloc132 5y ago

We are mostly targeting enabling GWT applications to be able to (relatively seamlessly) update to J2CL as a compiler, but are definitely interested in apps or libraries starting their lives as a plain Java project and expose it to JS/TS/closure in a variety of ways. Aside from the github repo, most of the conversation as we work on this happens at https://gitter.im/vertispan/j2cl https://gitter.im/vertispan/j2cl - feel free to stop by to ask any questions or share a use case that seems under-represented.