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A new, Java-based approach to cross-platform mobile apps (used by Google Inbox and Google Spreadsheets)
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What is JUniversal?

The vision of JUniversal came from some guys at Nokia who possess considerable expertise both in Java and in building cross-platform apps. They built this tool to provide an elegant way to translate source code and make it useful across multiple platforms. JUniversal offers you the freedom to write your shared code in Java and then translate it to C# (available now) or to C++/Objective C++ (coming soon). You can also combine JUniversal with Google鈥檚 j2objc translator to translate Java to Objective-C for iOS.
JUniversal is a tool in the Cross-Platform Mobile Development category of a tech stack.
JUniversal is an open source tool with 132 GitHub stars and 20 GitHub forks. Here鈥檚 a link to JUniversal's open source repository on GitHub

Who uses JUniversal?



JUniversal Integrations

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Public Decisions about JUniversal

Here are some stack decisions, common use cases and reviews by companies and developers who chose JUniversal in their tech stack.

Michael Xin Sun
Michael Xin Sun
Software Engineer at Google Inc | 2 upvotes 101.1K views
Shared insights

Comment from HackerNews (https://news.ycombinator.com/item?id=8998736)

This is how Google Inbox and Google Spreadsheets works. See the slides from my recently produced GWT Create Session (http://t.co/ZvoaHxCoZT). J2ObjC slide deck here (https://docs.google.com/presentation/d/1mW_Plm5jAygELf7qjVK7...) Videos of the conference will be online soon.

Prior to that, some 20% Googlers also produced the PlayN library (https://github.com/threerings/playn) This was taken over by Michael Bayne who added an iOS backend by Bytecode -> IKVM -> Mono conversion. I beleive j2objc and RoboVM backends exist now as well.

The major benefit of the j2objc approach is the avoidance of GC in favor of ARC, the conversion of message-sends into C-method calls when possible, and integration with existing iOS toolchain.

When we started, it seemed like an iffy idea, but after developing a product delivered to millions of users on a high volume site (gmail) that has 70% code sharing, and being able to simultaneously develop, test, and deploy across the platforms reasonably efficiently, a lot of skeptics have become converts to the concept. JUniversal

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JUniversal's Features

  • OAuth (based on Scribe)
  • JSON
  • Unit testing (JUnit)
  • File & network I/O platform wrappers
  • Collections鈥擧ashMap, ArrayList, etc. (based on JDK/Harmony)
  • Logging (based of SLF4J/Logback)
  • About 20K lines currently

JUniversal Alternatives & Comparisons

What are some alternatives to JUniversal?
React Native
React Native enables you to build world-class application experiences on native platforms using a consistent developer experience based on JavaScript and React. The focus of React Native is on developer efficiency across all the platforms you care about - learn once, write anywhere. Facebook uses React Native in multiple production apps and will continue investing in React Native.
Free and open source, Ionic offers a library of mobile and desktop-optimized HTML, CSS and JS components for building highly interactive apps. Use with Angular, React, Vue, or plain JavaScript.
Flutter is a mobile app SDK to help developers and designers build modern mobile apps for iOS and Android.
Xamarin鈥檚 Mono-based products enable .NET developers to use their existing code, libraries and tools (including Visual Studio*), as well as skills in .NET and the C# programming language, to create mobile applications for the industry鈥檚 most widely-used mobile devices, including Android-based smartphones and tablets, iPhone, iPad and iPod Touch.
Apache Cordova
Apache Cordova is a set of device APIs that allow a mobile app developer to access native device function such as the camera or accelerometer from JavaScript. Combined with a UI framework such as jQuery Mobile or Dojo Mobile or Sencha Touch, this allows a smartphone app to be developed with just HTML, CSS, and JavaScript.
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JUniversal's Followers
10 developers follow JUniversal to keep up with related blogs and decisions.
Hammad Ali
RanGeena Amarasena
Ryan Hicks
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