Shai is a JavaOne rockstar, top 10 JavaZone speaker and has been a professional software developer for over 20 years. Shai has been an active open source/Java community member has worked with countless companies in the field from top operators, phone manufacturers to banks and gaming companies. Shai consulted for Sun Microsystems (and Oracle) since the 90's where he was a core member/founder in high profile projects such as the WTK (worlds most successful mobile development platform prior to the iPhone), LWUIT etc. Shai is the co-founder of Codename One which allows Java developers to write native apps for all mobile devices iPhone/iPad, Android, Windows etc. Shai is a DZone MVB and is not an employee of DZone and has posted 3 posts at DZone. You can read more from them at their website. View Full User Profile

Codename One - Making WORA Real Again For Mobile Devices

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The iPhone was the first major phone to launch without Java, changing the landscape dominated by J2ME into a reality with a different kind of fragmentation. The open source Codename One project unifies the mobile platforms (iPhone, Android, Blackberry, Windows Phone 7 etc.) into a single API and tool stack based on Java. It allows developers to write code in Java and get native applications that can be installed on all mobile phones legally.

Codename One binds together years of work from multiple projects in the Java space to create a single coherent environment while allowing you to leverage the full power of Java tools directly from NetBeans/Eclipse. The API is Swing like with many improvements (proper styles/theming, painters, animations etc.) & yet allows full access to the underlying native device code. A standard GUI builder, simulator & IDE plugins are included and are all open source.
Seeing is believing so lets jump right to the code... After installing the Codename One Plugin (available for Eclipse/NetBeans) we now have a new Codename One project entry.   

 Codename One on the iPhone simulatorCodename One Android SimulatorCodename One Blackberry Torch Simulator

  We can create and run a new GUI builder hello world or non-GUI builder project in 30 seconds just by following the Wizard.
There is an active developer community forming around Codename One which can help you get started with the tool and answer the obvious questions.

Where's the catch?
There are several things you need to know:1. For maximum compatibility Codename One currently limits you to CLDC 1.1 syntax of Java. You can remove this limitation (by changing the build.xml file) but you will forfeit RIM/J2ME compatibility in the process.Even if these platforms aren't important to you we still wouldn't recommend doing this since you are more likely to stumble onto a Java SE feature that isn't supported by a target platform. In the future Codename One intends to slowly add additional API's and features from Java SE in a compatible and controlled manner.

2. Building for device requires sending the build to the server, this removes the need of owning a Mac for iOS builds or a Windows 7 machine for Windows Phone/Blackberry builds. Since Codename One is open source you can build locally from the source repository but its a very complicated process.  Using the build server is free for reasonable usage and we intend to keep it that way.

3. Currently you can't change the classpath. We intend to add a library mechanism which will allow 3rd parties to include "native" code in the library. You will need all your code in CLDC 1.1 source form, most of the API's you will need (XML/JSON parsers, UI etc.) are already included in Codename One.

 4. Codename One is new and its a work in progress, manage your expectations accordingly. However, we are very fast with the fixes and due to the years invested in the open source projects underlying Codename One the infrastructure is very solid. I will write more about what you can do with Codename One and how to accomplish it in a future post.
Published at DZone with permission of Shai Almog, author and DZone MVB.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)


Christian Schli... replied on Tue, 2012/04/10 - 2:59pm

Thank you very much for this post!

Jordi Böhme López replied on Fri, 2012/07/27 - 5:45am

Making WORA Real Again For Mobile Devices? Thats not quite right...

There is Tabris out there that makes Write Once Run Anywhere real, too - as well with Java - but uses native Widgets instead of a theme or static graphics - so it looks/feels better imho.

Shai Almog replied on Fri, 2012/07/27 - 7:05am in response to: Jordi Böhme López

If I understand correctly Tabris is a "runner" platform/server based container solution.

While it might be fine for some it is NOT like Codename One which is a true native mobile platform that generates a standalone native application that's unique, royalty free and allows invoking native device code (objective-c, dalvik etc.).

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