Show HN: Java 7 Features Backported to Android

https://github.com/yareally/Java7-on-Android

by yareally • 13 years ago

49 33 13 years ago

luke_s2• 13 years ago

Since you have to read a long way through the FAQ to find out, here are the answers to the two most important questions I had:

   Q) So what works from Java 7?

   A) All the syntatic sugar stuff and also "try with resources." (see below)

   1) String Switches

   2) Try with resources (a.k.a "using/with", auto close)

   3) Multiple exception caught in one catch block

   4) Integer (and binary) literals for readability (e.g. 100_000_000 or 20_000 or 0b0111_0000)

   5) Type inference on collections (a.k.a. "diamonds")


   Q) What doesn't work?

   1) java.nio.*

   2) threading and multiple processor enhancements (fork/join)

   3) File change notifications (watch/notify file api stuff)

   4) invokedynamic

Its unfortunate that google haven't worked to bring more modern java language features to Android, although I imagine that the Android group has been kept rather busy with other things. Still, Google io is coming, with what is sure to be a slew of new product and feature announcements, so one can hope ...

yareally7• 13 years ago

Sorry about burying the most important questions. I moved them to the top of the FAQ now :)

I really wish Google would just make amends with the Apache Foundation and work with them on improving OpenJDK. It would be so much better for both (and us developers) if they did.

All the unimplemented stuff falls under more than a weekend project and not sure how nice some of it would play with Android's APIs and Dalvik. The only thing I would really love to see outside of what was able to easily get working is Lambdas.

luke_s2• 13 years ago

I was following the goings on between the ASF and Sun/Oracle a while back, but I was un-aware that ASF and google also had problems! What was the nature of their disagreement?

I think lambdas is the one killer feature I would love to see in Android/Java - particularly for a framework such as Androids which is so callback heavy, lambdas would be an immense help.

drorweiss• 13 years ago

Well done!

On a related note - is using Scala also a viable option for android? Anybody tried?

koko7755• 13 years ago

Sort of. It has issues with ProGuard, but the Scala standard library is a couple of megabytes, so you'll be adding some size to your application, or you'll have to very carefully test and configure.

Additionally, Dalvik didn't have JIT until late in its maturity, so besides the normal slowdown from Java->Scala, expect it to slow down further by the less-efficient VM.

It might be viable on newer devices, but it'll definitely have problems on older ones. Other than that, it does seem very feasible to write and deploy a Scala Android app.

yareally7• 13 years ago

Kotlin might have a better time on Android (though I too would prefer Scala), or at least better support. I haven't tried it yet on Android, but Jetbrains had a small tutorial for it on their blog[1]. I've just been putting it off since it was an immature language, but that may not be quite as true now.

[1] http://blog.jetbrains.com/kotlin/running-hello-kotlin-on-and...

happy_dino3• 13 years ago

There are pretty much no issues using Scala on Android. After running ProGuard, the Scala library takes up a few dozen kilobytes.

Execution is as fast as Java. I remember running my Scala app on one of the first tablets (Android 2.x) without issues.

The build system support is impressive and there is a whole community which focuses on Scala running on Android.

pjmlp5• 13 years ago

I think using Kotlin[1] or Xtend[2] might be a better option, because the projects explicitly support Android, while Scala and Clojure support are side projects by the community.

[1] http://kotlin.jetbrains.org/

[2] http://www.eclipse.org/xtend/

trailfox• 13 years ago

Kotlin looks pretty nice (even as a dumbed-down Scala), but it hasn't even hit beta yet. I have yet to meet anyone actually using xtend.

mhaymo2• 13 years ago

I tried and failed, although admittedly there were other factors at play. Bump tried and succeeded, but it took a lot of work: http://www.slideshare.net/michael.galpin/scala-on-android-ex...

pjmlp5• 13 years ago

Nice work.

I am starting to think Google will leave Java language support at Java 6 level, or eventually offer full native support, instead of the half solution that the NDK currently offers.

Looking forward to this year's Google IO to see if there will be any change at that level.

koko7755• 13 years ago

It's not impossible for Google to work out a licensing deal with Oracle, but I'd just as soon expect them to come up with their own LLVM-based language implementation or announce LLVM support for one they've already developed, given that they added Clang (and thus, LLVM) support to NDKv8 in November 2012.

pjmlp5• 13 years ago

That is exactly what I have been thinking as well.

neeee• 13 years ago

I'd love seeing decent support for Go on Android.

Show HN: Java 7 Features Backported to Android

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