5 ms·

While I appreciate the tecnological background of this project, I don't like this kind of traslators. It could be useful if you need to execute Java code in Ob

by resca79 12y ago

While I appreciate the tecnological background of this project, I don't like this kind of traslators. It could be useful if you need to execute Java code in Objective-c runtime, but not if you want develop iPhone/iPad app. Obj-C is simple, the problems are the iOS frameworks that you need to learn to delivery an iOS App. If you are Java skilled, anyway you need to learn these frameworks, and you will spend your time to traslate the examples(stackoverflow) from obj-c to java I'm not a xcode fans, but it is a great tool when you use the StoryBoard and all features to test, performance, memory .. etc. Another point is that with the introduction of the Swift language this traslator loses other value

cromwellian 12y ago
The purpose of j2objc is not to address a single platform. It's not to write code in Java in order to deliver an iOS only app. It's to share logic across multiple platforms. If you combine j2objc and GWT together, you can share code between Web, native Android, and native iOS, while writing the UI in JS, Objective-C with InterfaceBuilder/Xcode, or native Android Views. If you want to share non-UI code across all three platforms you have these kinds of choices: * js everywhere (WebView wrapper or embedded JS interpreter on iOS) * C everywhere (emscripten/NaCl on WEB) * Java everywhere (GWT->js for Web, j2objc for iOS) I can only speak from experience, but option three worked fantastically.
- matthewmacleod 12y ago
  I've often heard this idea about 'sharing logic across multiple platforms'. I agree that it's a noble goal, but I'm curious about places where that sort of logic is actually common enough to justify the overhead of maintaining a cross-platform library. Most of the applications on my phone are ultimately native UI skins over web services. There might be some logic in there to handle other features, but in most cases it's tied into OS-native features anyway. I can see cross-platform libraries being useful for games using GL, maybe for media applications that require formats not supported by the OS, and for applications that do heavy image or audio processing – in short, the sort of thing where the value-add is specifically high-performance processing. Maybe that's enough to justify the existence of these tools, though I'd imagine it's almost always a better option to write your library in C in the first place.
  - cromwellian 12y ago
    Case in point: Inbox by Gmail. It is not just a thin skin over AJAX calls, but actually a fairly sophisticated client side application.
    - betteringred 12y ago
      Does Google Inbox use J2ObjC? You seem to be alluding to that but not explicitly saying it.
      - bookwormAT 12y ago
        Google Inbox is indeed written in J2ObjC: See https://groups.google.com/forum/#!topic/j2objc-discuss/5lMZNzl5Si0 https://groups.google.com/forum/#!topic/j2objc-discuss/5lMZN...
    - akrymski 12y ago
      > a fairly sophisticated client side application is it actually an full blown IMAP client? Most likely it uses AJAX to fetch JSON from Google's proprietary APIs
      - cromwellian 12y ago
        It works offline, that should give you a clue that it is not just a request/response app. Yes, it does make requests to Google's servers, but it can run completely offline with no connection as well.
  - MarkMc 12y ago
    I think you're underestimating the amount of platform-independent code in a typical app. Looking though a random sample of non-game apps on my iPad, I'd guess that about half would have a significant chunk of code which is not OS-specific, including: Gmail, Spotify, Anki, Google Maps, Facebook, Twitter, Penultimate. I also don't think that the choice between C and Java as the common language is so clear cut. C would get you some speed benefit but Java has GWT for porting Java to Javascript, and and a huge range of other tools and libraries. In the end I think it would come down to how comfortable your development team was in each language. (Disclaimer: I'm a Java developer)
- resca79 12y ago
  Sharing the business logic makes sense, but I'm not confident that sharing code on web and mobile devices is a good point in terms of performance. The UI in JS is simple to develop, but you have a lack of performance also
  - m_mueller 12y ago
    From my experience with servers-side JS code, if your JS is fast enough to run with every server request, it's also fast enough to run on today's mobile processors. Obviously for Client-side code this isn't true, but then again if you want your apps accessible from mobile browsers, you need to have it reasonably optimized anyway.
robmccoll 12y ago
> Obj-C is simple Yeah you just need to know C, possibly C++, and smalltalk and be comfortable using the syntaxes for all three simultaneously. For the record though I'm a big fan of C and C++, and I don't really care for Java. I can just see why people who already know Java well would want to use Obj-C as little as possible.
- resca79 12y ago
  You don't need to learn 3 languages to be skilled in Obj-c Just for one reason, there are many iOS developers in the world, and at the same time C++ and C developers are few today.
  - pjmlp 12y ago
    If your imagine of the world is USA, maybe true.
  - andyjohnson0 12y ago
    "... C++ and C developers are few today." In a web/js/Ruby/mobile echochamber that may be true. But in the real world C/C++ is very far from being a minority skillset. Take a look at [1][2][3]. C, C++, and Java are the main languages in use today. [1] http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html http://www.tiobe.com/index.php/content/paperinfo/tpci/index.... [2] http://langpop.com http://langpop.com [3] http://lifehacker.com/the-top-programming-languages-ranked-by-job-demand-po-1601752302 http://lifehacker.com/the-top-programming-languages-ranked-b...
    - resca79 12y ago
      You need look at the growing data. Maybe the number of people that know c or c++ are more for the ages of the languages itself. Try to look any statistics about github[1] [2] [1] http://redmonk.com/dberkholz/2014/05/02/github-language-trends-and-the-fragmenting-landscape/ http://redmonk.com/dberkholz/2014/05/02/github-language-tren... [2]http://sogrady-media.redmonk.com/sogrady/files/2014/02/repos-by-lang-github1.png http://sogrady-media.redmonk.com/sogrady/files/2014/02/repos...

by resca79 12y ago

cromwellian 12y ago

The purpose of j2objc is not to address a single platform. It's not to write code in Java in order to deliver an iOS only app. It's to share logic across multiple platforms. If you combine j2objc and GWT together, you can share code between Web, native Android, and native iOS, while writing the UI in JS, Objective-C with InterfaceBuilder/Xcode, or native Android Views. If you want to share non-UI code across all three platforms you have these kinds of choices: * js everywhere (WebView wrapper or embedded JS interpreter on iOS) * C everywhere (emscripten/NaCl on WEB) * Java everywhere (GWT->js for Web, j2objc for iOS) I can only speak from experience, but option three worked fantastically.

matthewmacleod 12y ago
I've often heard this idea about 'sharing logic across multiple platforms'. I agree that it's a noble goal, but I'm curious about places where that sort of logic is actually common enough to justify the overhead of maintaining a cross-platform library. Most of the applications on my phone are ultimately native UI skins over web services. There might be some logic in there to handle other features, but in most cases it's tied into OS-native features anyway. I can see cross-platform libraries being useful for games using GL, maybe for media applications that require formats not supported by the OS, and for applications that do heavy image or audio processing – in short, the sort of thing where the value-add is specifically high-performance processing. Maybe that's enough to justify the existence of these tools, though I'd imagine it's almost always a better option to write your library in C in the first place.
- cromwellian 12y ago
  Case in point: Inbox by Gmail. It is not just a thin skin over AJAX calls, but actually a fairly sophisticated client side application.
  - betteringred 12y ago
    Does Google Inbox use J2ObjC? You seem to be alluding to that but not explicitly saying it.
    - bookwormAT 12y ago
      Google Inbox is indeed written in J2ObjC: See https://groups.google.com/forum/#!topic/j2objc-discuss/5lMZNzl5Si0 https://groups.google.com/forum/#!topic/j2objc-discuss/5lMZN...
  - akrymski 12y ago
    > a fairly sophisticated client side application is it actually an full blown IMAP client? Most likely it uses AJAX to fetch JSON from Google's proprietary APIs
    - cromwellian 12y ago
      It works offline, that should give you a clue that it is not just a request/response app. Yes, it does make requests to Google's servers, but it can run completely offline with no connection as well.
- MarkMc 12y ago
  I think you're underestimating the amount of platform-independent code in a typical app. Looking though a random sample of non-game apps on my iPad, I'd guess that about half would have a significant chunk of code which is not OS-specific, including: Gmail, Spotify, Anki, Google Maps, Facebook, Twitter, Penultimate. I also don't think that the choice between C and Java as the common language is so clear cut. C would get you some speed benefit but Java has GWT for porting Java to Javascript, and and a huge range of other tools and libraries. In the end I think it would come down to how comfortable your development team was in each language. (Disclaimer: I'm a Java developer)
resca79 12y ago
Sharing the business logic makes sense, but I'm not confident that sharing code on web and mobile devices is a good point in terms of performance. The UI in JS is simple to develop, but you have a lack of performance also
- m_mueller 12y ago
  From my experience with servers-side JS code, if your JS is fast enough to run with every server request, it's also fast enough to run on today's mobile processors. Obviously for Client-side code this isn't true, but then again if you want your apps accessible from mobile browsers, you need to have it reasonably optimized anyway.

robmccoll 12y ago

> Obj-C is simple Yeah you just need to know C, possibly C++, and smalltalk and be comfortable using the syntaxes for all three simultaneously. For the record though I'm a big fan of C and C++, and I don't really care for Java. I can just see why people who already know Java well would want to use Obj-C as little as possible.

resca79 12y ago
You don't need to learn 3 languages to be skilled in Obj-c Just for one reason, there are many iOS developers in the world, and at the same time C++ and C developers are few today.
- pjmlp 12y ago
  If your imagine of the world is USA, maybe true.
- andyjohnson0 12y ago
  "... C++ and C developers are few today." In a web/js/Ruby/mobile echochamber that may be true. But in the real world C/C++ is very far from being a minority skillset. Take a look at [1][2][3]. C, C++, and Java are the main languages in use today. [1] http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html http://www.tiobe.com/index.php/content/paperinfo/tpci/index.... [2] http://langpop.com http://langpop.com [3] http://lifehacker.com/the-top-programming-languages-ranked-by-job-demand-po-1601752302 http://lifehacker.com/the-top-programming-languages-ranked-b...
  - resca79 12y ago
    You need look at the growing data. Maybe the number of people that know c or c++ are more for the ages of the languages itself. Try to look any statistics about github[1] [2] [1] http://redmonk.com/dberkholz/2014/05/02/github-language-trends-and-the-fragmenting-landscape/ http://redmonk.com/dberkholz/2014/05/02/github-language-tren... [2]http://sogrady-media.redmonk.com/sogrady/files/2014/02/repos-by-lang-github1.png http://sogrady-media.redmonk.com/sogrady/files/2014/02/repos...