Why I don’t recommend using GoDaddy for Hosting

This has come up a few times now on the Xataface forum. Users write into the forum because their Xataface application has stopped working — or at least everything except the homepage has stopped working. They report errors like “Connection reset” in their browser, or simply a blank white page. Their PHP error log is empty, and their access log also is devoid of any evidence that any HTTP requests have even occurred.

The cause:

GoDaddy’s mod_security settings. In particular, their rule that any HTTP request where the query string begins with a hyphen (“-“) will be blocked. This causes lots of problems for Xataface because it uses a convention that many of the query parameters must begin with a hyphen.

Here is a simple test to see what I mean (if you use GoDaddy).

Create a simple PHP script named hello.php with the following contents:

echo "hello world";

Then copy it to your GoDaddy server and try to access this script in your web browser at

It should display “hello world” as you expect. Now try adding a query string to the URL that begins with a hyphen:

This request will fail. Either your browser will hang or you will just receive a connection reset error.

From experience, if you try to contact GoDaddy support to explain the problem, they will suggest that it is a problem with your code and will deny that they are blocking requests. I have heard reports from 3 or 4 people who have gone through this process. Ultimately they end up having to find different hosting.

There are lots of good, low cost, shared hosting providers out there that provide good service without having to deal with intrusive filtering like this. Personally, I’ve had pretty good luck with Dream host, but there are countless out there that should work fine. I do understand the value in trying to block malicious HTTP requests, but there is nothing malicious about a hyphen.

GoDaddy may not be the only host with this restriction. I encourage you to try the hello world litmus test from this article on your host before getting to comfortable with them. If they are blocking requests like that, and are unwilling to remove the filter, you don’t want to waste your time with them.

Shape up, GoDaddy!

Make the World A Better Place by Making A Codename One Library

Codename One recently opened up a plugin repository on their website where you can download libraries to extend the functionality of Codename One. Right now it is really just a static webpage because the list of available modules is small. Let’s change that! I cannot think of an easier platform to develop modules for. There is a Netbeans project type that does all of the packaging work for you.

All you have to do is write your code and hit build. Then upload it to GitHub (or wherever you want to host it) and let the CN1 folks know that your module exists.

What Kinds of Modules Should I Build?

UI Components

The Codename One UI Component model is both simple and flexible. It is modelled loosely after Swing (e.g. Base “Component” class, a “Container” class which is a component that can contain other components, Label, Button, TextField, etc..) but they ditched a lot of the chaff and bloat to come up with a solution that light, simple and portable.

Creating a custom component is as simple as subclassing the Container class (or Component) and laying out some child components inside it. Once you have your custom class, you can package it up in as a cn1lib, and upload it to github. Don’t forget to write some javadocs and examples for it so people know how to use it.

I see requests in the mailing list all the time asking whether Codename One has a component that does X. The answer is often “yes”, but if the answer is no, I generally don’t hear anything else – even though the asker has likely gone off and implemented it themselves for their application. I saw a recent request for a “Color Chooser” component. Such a component would be relatively easy to create using the CN1 API. Create a dialog that gives a few slider controls to select RGB, provide some callbacks and public methods to be able to obtain the selected color, and you have a reusable color chooser component that the whole community can enjoy.

Data Processing

If you find yourself solving a problem that involves converting data from one format to another (e.g. extracting or compressing a ZIP file, MP3 Encoding, etc..) why not wrap it in a cn1lib so that others can use and improve your library.

One of the main strengths of Java was that you could almost always find a 3rd party library to do what you need. Because Java follows strict standards for name-spacing, documentation, and packaging (jar files) you could find, download, and learn how to integrate modules into your application without having to spend days looking through code to see how it works.

Having a healthy ecosystem of 3rd-party libraries is preferable to having one large monolithic core because it allows us to streamline our applications to our particular purposes and not be weighed down by features we don’t need. Many processing tools don’t belong in the CN1 core because they are too niche.

If you are developing a method to do something useful, think for a moment whether this method might be useful to someone else. You might have to make some changes to your design to decouple your library from the rest of your app – but this is a good idea anyways.

Native Functionality

Codename One is a cross-platform tool for mobile development. However it also allows you to tap into native functionality if needed by writing native interfaces (sort of like JNI, but easier to user IMO). Does your application target a platform on which you want to make use of some native libraries? Then you’ll have to write a native interface to access them. If you’re going to write a native interface anyways, why not write it in such a way that it can be reused in other projects.

The iOS, Android, and Windows Phone SDKs have tons of goodies. Usually I try to find a cross-platform solution for a requested feature, but in some cases your app will be better for making use of native APIs. If we all do our share, and publish native interfaces in cn1libs as we write them, we collectively make the Codename One ecosystem richer and more capable. And all of our apps will get better.

HTML5/Javascript Components

The big 3 platforms (iOS, Android, and Windows Phone) all support HTML5 inside the BrowserComponent in Codename One. This opens up a lot of possibilities for integrating HTML5 components into your codename one apps. There are countless Javascript/CSS libraries and components that can easily be ported to Codename One. You can even use the Codename One Javascript bridge to communicate between Java and Javascript.

A word of caution with including HTML inside your Codename One apps. HTML components are much more difficult to debug than Java components because you don’t get the nice stack trace. Generally, I find it best to debug as much HTML/Javascript as I can separately inside Chrome, then integrate it into CN1 with as few Java-Javascript dependencies as possible.

Port Existing Java Libraries

This type of library can be, arguably, the most useful for the CN1 ecosystem. You can’t just use a regular Jar with Codename One because it only supports a subset of the libraries in JavaSE. The Codename One class library includes basically the CLDC 1.1 less the javax.microedition.* classes. It also includes a number of other classes that have been added as needed (e.g. the Java Collection classes) in addition to a number of its own packages under the com.codename1.* namespace. You can check out the Codename One javadocs for a full list of supported classes.

For porting existing Java libraries to Codename One, I generally try to find a J2ME library that does what I want, since J2ME is closest to CLDC. I then go through all of the source files and look at the import sections (at the top of each source file) to see if any classes outside of the java.io, java.lang, and java.util packages are used. If I find any dependencies outside of these packages, I take a closer look to see how easy it would be to remove the dependency. Sometimes I can find another class in the Codename One SDK that will do something similar, or I might just disable some of the functionality of the library if it isn’t needed.

After removing all of the illegal dependencies, I create a new Codename One Library project in Netbeans, and copy the library’s source files into the project. Building this project will force compliance with the Codename One libraries. If the project builds successfully, then you will have a library that is compatible with all devices on Codename One.

Performance: J2ME libraries will generally use the Thread-safe collection classes (e.g. Hashtable and Vector) instead of their faster cousins (HashMap and ArrayList). Since Codename One supports the more modern collection classes, and these perform much better, I generally go through libraries that I have ported from J2ME and change all references of Vector and Hashtable to ArrayList and HashMap respectively. I also replace StringBuffer instances to StringBuilder for the same reason.

JavaSE Libraries: JavaSE libraries can be trickier to port because they often rely on many classes that fall outside of the Codename One SDK. If they make heavy use of AWT and Swing then you might have difficulty finding Codename One equivalents to maintain the functionality. You may have to take some time to understand how the library works so that you can figure out how best to substitute out the illegal class references. The recent release of the CN1Pisces library means that you should now be able to port over most Java2D code into Codename One by changing calls from Java2D into the equivalent Pisces or Codename One Graphics calls.

A Word about the cn1lib File Format

If you are a Java developer, you might be wondering why the CN1 guys didn’t just use jars to distribute libraries. There are two reasons:

  1. Libraries may need to package both java and native code together in a standard way so that they can include native implementations. The cn1format supports this, while jar does not have a standard way of doing this.

  2. Codename One supports a slightly different API than standard Java so, for any given jar file, it is unlikely that CN1 will work with it without some modifications. Having its own format helps to ensure that all code in a cn1lib file is actually supported in Codename One. In this way it serves as a sort of compliance test.


There are only so many hours in the day to develop cool things, so I would prefer to develop components that work on as many devices as possible. Codename One has provided us with a platform for building cross-platform mobile apps that doesn’t have the same performance sacrifices as other cross-platform solutions. The foundation is strong. The user interface is built on a high-performance, light-weight stack that takes advances of hardware accelerated graphics. All code is compiled to native code so it should run just as fast as native, and sometimes even faster.

This is a foundation that we can build on. So let’s take advantage of it.

Git Hub, Codename One Javascript Components , PDF CJK Fonts

I haven’t posted in a while, mostly because I haven’t had time. I just wanted to post a short update on my development activities over the past while. One big thing to note is that I have finally adopted Git as my primary source version control system. I had been using SVN for years, but once I started playing around with Git it was clear that I had to make the move. Git is much faster for checking out and committing. It also makes branching and merging much easier than with SVN. The most compelling feature of Git, though, is Git Hub. It provides a much easier way to share my code with the world, and it makes it a simple matter for others to contribute.

My Github page

I have created repositories for Xataface and many of its modules on GitHub. I have also moved SWeTE over.


I recently developed a library for PDFClown to support Chinese, Korean, and Japanese fonts. This is a feature that is nowhere to be found in the world of open source PDF editors (iText is excluded from this list because of its AGPL license). Check out the source for this module on the github project page.

Codename One Javascript Components

I have also created a few Codename One wrappers for Javascript components. So far I have created a charting module, and a rich text editor module. Both use my Javascript bridge for the Java-Javascript communication. I created these, partly, as a proof of concept. Codename One sits at a unique junction between Java, Native, and Javascript. The ideal situation is to have as much as possible implemented in pure Java so that it is available across all platforms (JME, BlackBerry, Windows Phone, Android, and iOS), but the fact is that there are thousands of mature, well-supported Javascript libraries that can nicely complement the codename one toolbox. Javascript components should be compatible with the big 3: WinPhone, Android, and iOS.. Any platform that supports a native browser component.

One issue that I have faced is that the Codename One build server currently doesn’t retain package structure for resources on iOS and WinPhone. All resources are just flattened into the topmost directory of the application bundle. This is a pretty big problem for Javascript components since most will consist of a directory of resources including javascript, CSS, HTML, and image files, and they depend on their relative package structure.

The problem has been reported in issue 809. There are two possible current workarounds:

  1. Use offline builds for iOS. These support package structures for resources.
  2. Try to embed everything into a single HTML file, and then embed this file as a String in a Java class. I used this strategy in the Charts module – everything is embedded into a package private Resources class.

CFIB Study on Municipal Spending Incorrect and Misleading

In the last few days, CKNW has been touting a new study by the CFIB (Canadian Federation of Independent Business) claiming that spending in the four largest cities in Canada is growing out of control. Specifically (in Vancouver) they claim that spending from 2000 to 2011 grew by 50% while population only increased by 15%.

Since this is only comparing 3 metrics (spending, inflation, and population growth), it should be easy to check out their numbers. Based on the City of Vancouver financial statements and the reported inflation in Canada, I find that their numbers on spending are both misleading and WAY off.

We have reports from 2000 to 2012, but to align with their study, I’ll talk about the changes from 2000 to 2011 only. Accounting for inflation, there has been an increase in spending of 40% from 2000 to 2011 (736 million in 2000; 1.03 billion in 2011 (in 2000 dollars)). This is lower than the 50% increase claimed in the study.

Further, the data shows that spending in 2011 and 2012 is actually lower than it was in 2008 (adjusted for inflation). If they want to complain about spending being out of control, they should look to the years 2000 to 2008 when spending increased by 55% adjusted for inflation. Since 2008, spending has decreased by 8 percent!

Of course, that would make this study 5 years too late!

I have created a spreadsheet with my calculations.


  1. Vancouver City Financial Reports
  2. Canada Historical Inflation
  3. CFIB Study


Initially I had stated that spending was up 24% from 2000 to 2011. Actually it is up 40%. That doesn’t change the fact, however, that spending is down since 2008.

Object Persistence in Codename One

One very useful feature of Codename One is its Storage class, which provides a cross-platform key-value store that can be used to store simple data (e.g. Strings, Integers, Doubles), large binary data (e.g. byte arrays of encoded movies or images), and custom data types (i.e. your own objects). Storage is not shared between applications so it is like your own persistent Hashtable that allows you to store anything you might need for your application.

The API is simple. It provides methods to read objects, write objects, delete objects, check for object existence, and listing objects that are currently stored in storage. All lookups are based on key-value lookups.

A simple example:

Storage s = Storage.getInstance();

// Save the "Hello World" string to storage
s.writeObject("mystring", "Hello World");

// Read my "Hello World" string back from storage
String hello = (String)s.readObject("mystring");

// Delete my string from storage

Just as we stored a String, we could have stored a Vector of Strings, or a Hashtable of key-value pairs, or a tree of Vectors and nested Hashtables. The only caveat is that the Vectors and Hashtables can only contain objects that can be externalized.

What Can Be Externalized?

I don’t have a definitive list of what can be externalized in Codename One, but in general, you can externalize:

  • Primitive types (e.g. int, float, long, double, byte, etc..)
  • Arrays of primitive types (e.g. int[], float[], long[], double[], etc..)
  • Strings
  • Vectors
  • Hashtables
  • Objects implementing the Externalizable interface.

Hence, if you want to save your own custom objects in Storage, you need to implement the Externalizable interface. It is worth noting that you can’t simply implement the Serializable interface as you do in regular java. You need to implement Codename One’s externlizable interface that explicitly defines how to read and write the objects to/from a DataOutputStream/DataInputStream. This is due to the fact that Codename One doesn’t support reflection. In addition to implementing the Externalizable interface, you also need to register your class with CodenameOne (via the Util.register() method) so that it knows which class to use when deserializing your objects.

Saving Custom Types to Storage

As mentioned above, any object that you want to persist to Storage must implement the Externalizable interface. If you try to save objects that don’t implement this interface it will raise an exception. If you, subsequently try to read an object that hasn’t been registered with Codename One via the Util.register() method, then Storage.readObject() will simply fail silently and return null. This will occur, if any object in the graph that you are trying to read is not registered.

The Externalizable interface requires 4 methods:

  1. getVersion() – This should return the version of your object. This will be used to record the version of the object when it is written to storage. This value will be passed to your internalize() method when you read the object so that you can handle old serialization structures properly when you modify your class.
  2. getObjectId() – This should return a unique String ID for the class (not the object as the method name seems to indicate). This should match the id that is registered with Util.register() so that it knows which class to instantiate when loading objects from a DataInputStream. But you could use anything here, as long as you use the same ID in the Util.register() method.
  3. externalize() – This method should write your object to a DataOutputStream.
  4. internalize() – This method should read your object from a DataInputStream.

Your class should also include a public constructor that takes no arguments.

Example Class:

Let’s look at a simple example class for a user profile.

class Profile {
    public String firstName, lastName;
    public int age;
    public List<String> emails = new Vector<String>();

Note that I’m making all of the members public for simplicity and to reduce code in this example. Normally you would probably make the members private and implement setter/getter methods to access them.

Now, let’s implement the Externalizable interface on this class:

class Profile implements Externalizable {
    public String firstName, lastName;
    public int age;
    public List<String> emails = new Vector<String>();
    public int getVersion() {
        return 1;

    public void externalize(DataOutputStream out) throws IOException {
        Util.writeUTF(firstName, out);
        Util.writeUTF(lastName, out);
        Util.writeObject(emails, out);

    public void internalize(int version, DataInputStream in) throws IOException {
        firstName = Util.readUTF(in);
        lastName = Util.readUTF(in);
        age = in.readInt();
        emails = (List<String>)Util.readObject(in);

    public String getObjectId() {
        return "Profile";


I want to comment on a few things here that are important:

  1. The order in which we read members from the DataInputStream in the internalize() method must be exactly the same as the order in which we write them in the externalize() method.
  2. We use Util.writeUTF() to write Strings instead of the DataOutputStream’s writeUTF() method, because it handles null values. I.e. if you try to pass a null string to the DataOutputStream’s writeUTF() method, it will throw a NullPointerException.
  3. We use Util.readObject() Util.writeObject() for writing objects (like the Vector containing email addresses). DataInputStream/DataOutputStream don’t provide equivalents.

Reading and Writing Profiles

Now let’s test out our class:

Profile steve = new Profile();
steve.firstName = "Steve";
steve.lastName = "Hannah"

Storage s = Storage.getInstance();
s.writeObject("steve", steve);

Profile newSteve = (Profile)s.readObject("steve");

System.out.println("Profile first name : "+newSteve.firstName);

If you try to run this example you’ll get a NullPointerException when you try to access the firstName property of newSteve. If you retrace your steps, you’ll find that the object was written OK (you can use the Storage.listEntries() method to see what keys are stored in storage). It’s just that the line:

Profile newSteve = (Profile)s.readObject("steve");

returns null. This is because we forgot to register our Profile class with Util, so it didn’t know which class to use for deserialization. If we add the line:

Util.register("Profile", Profile.class);

at any point before we try to read the object from storage, then it will work as expected. This is a big gotcha.

Tip: If you are getting null values out of storage, you should make sure that you have registered classes for ALL objects that are being read, including nested objects.

Where to Place Registration Code?

I’m still sorting out where the best place is to store the code that registers a class with Util. Here are a few options:

  1. Explicitly register all classes that you are using inside your application’s controller (e.g. in the start() method). If your application is self contained, this may be the simplest way. However, if your app may be using classes from external libraries, you may find it difficult to identify all of the possible classes that you may need to retrieve from storage.
  2. Inside a static block for the class that implements the Externalizable interface. e.g.

    public class Profile implements Externalizable {
        static {
            Util.register("Profile", Profile.class);

    This will work, if you have referenced the class from somewhere inside your code before you unserialize the object. However, if your object is nested and its class is not referenced directly from code, then this static block may not be run before the object is deserialized (which will result in readObject() returning null).

    For example, we might load a Vector of Profiles like this:

    Vector v = Storage.getInstance().readObject("profiles");

    If we don’t explicitly reference Profile in our code, here, then this will fail (silently) because the Profile class will not be registered yet. However, if we first reference the Profile class, it will work. E.g.

    Profile p = new Profile();
    Vector v = Storage.getInstance().readObject("profiles");

  3. Other ideas? You can place the registration code anywhere you like. You just have to be aware of when/if your registration will be run vs when your objects are likely to be read from Storage.

Trouble Shooting

During my experiments with Storage, I ran across a few "gotchas" that you should watch out for:

  1. Object keys cannot be "paths". I.e., don’t include the "/" character in the key for write/readObject or you may get some unexpected results. E.g.
    Don’t do:

    byte[] b = new byte[]{'a','b','c'};
    Storage.getInstance().writeObject("bytes/foobar", b);

    Or you will get an error like:

    java.io.FileNotFoundException: /Users/shannah/.cn1/bytes/foobar (Not a directory)

    I’m not sure if this is a bug, but it’s something to watch out for. You can use any other character you want. Just don’t use a slash!

  2. Make sure ALL objects in your hierarchy that you are saving implement the Externalizable interface (or are supported natively by CN1 eg. Vector, Hashtable, etc..)
  3. Make sure you have run Util.register() for ALL classes that will be read from storage before trying to read them from storage. If you do not do this, Storage.readObject() will fail silently, returning null.
  4. Use Util.writeUTF()/Util.readUTF() when writing/reading Strings in your externalize() method. Don’t use out.writeUTF() because this will throw a NullPointerException for null strings.
  5. Use Util.writeObject()/Util.readObject() for writing/reading objects inside your externalize()/internalize() methods. There is no equivalent in DataOutputStream/DataInputStream.

Two Months with the Nexus 7

I have now had the Nexus 7 for a little under two months so I thought I’d post a mini-review of the product.

I purchased the Nexus 7 because I needed a newer Android test device for my development and I had heard good things about it.

The Good

It is very light. Compared to my first generation iPad, it is a joy to hold while I read the web in bed.

Easy and intuitive setup. The interface of Android 4.2 seems to be much improved over my previous android device (2.2). Installing apps and switching between apps is fast and efficient.

Development is easy. Compared to my iPhone where I had to jump through an endless series of hoops, just to get my own apps running on my device, the Nexus 7 was as simple as plug it in and go.

The price. At $199 you can’t complain.

The Bad

Battery life. My first generation iPad can sit on the table unused for weeks, and still have a full battery charge. With the Nexus 7, I can put it in my bag with a full charge, and it will be empty the next time I want to use it 3 days later.

Scrolling. Compared to my first gen iPad (which is 3-year-old technology), the scrolling is jerky and sluggish in most apps. It seems that Android is still playing catch-up on the usability scale.

Soft keyboard. Once again, comparing to my iPhone and 1st gen iPad, the keyboard is more difficult to use on the Nexus 7. The autocorrect is frequently wrong, and it doesn’t seem to get as good at guessing which key I intended to type.

The Case For Light-Weight UI Toolkits

This post is motivated by a recent Reddit thread where someone posted an announcement about the 1.0 release of Codename One, a toolkit for building cross-platform mobile applications. I was quite surprised by the stream of negativity in the responses from developers who had never tried the framework, but who mistakenly assumed that they knew everything about it because they have tried other cross-platform toolkits in the past.

Before I discuss the thread itself, I just want to take a minute to talk about light-weight UIs and why they are important.

Light-Weight UI vs Heavy-Weight UI

When people refer to a light-weight user interface toolkit, they are generally referring to a toolkit where all of the widgets and components are drawn using graphics primitives using the toolkit itself. A heavy-weight user interface, on the other hand, is one where the components from the underlying platform are just placed in the user interface, and aren’t drawn manually. Swing, JavaFX, HTML5, QT, and Codename One are examples of light-weight UI toolkits. AWT, SWT, and Appcelerator Titanium are examples of heavy-weight UI toolkits.

Why Are Light-Weight UI Toolkits Important for Cross-Platform Development?

When you are developing for multiple platforms, then a heavy-weight UI will be one that addresses the lowest common denominator. If every platform has a “Text box” widget, then you can safely add a text box to your UI, and the correct widget will be shown on the current platform. But if one of the platforms doesn’t have a text box widget, you need to either say that “text boxes aren’t supported on platform X”, or you have to come up with an alternative for that platform.

With a light-weight UI, every platform can have a text box because you don’t depend on the underlying platform for the actual widget. This opens quite a bit of flexibility.

It is kind of like the difference between creating art work with stickers vs painting the art directly onto canvas. Imagine you are teaching an art class via a webcast and you have 5 different art students each with their own toolkit. These toolkits consist of a set of stickers and stamps that they have brought from their own collection, and a paint set. For the “heavy-weight” portion of the class, you would be instructing the students to place stickers onto the canvas. E.g. You might say “Now place a sticker of a dog in the top right corner”. But what if some of the students don’t have a sticker of a dog? Then you might say, “If you don’t have a dog, just use a cat. And if you don’t have a cat, then just leave the space blank”.

At the end of the lesson, the art work produced by each student would be radically different. The stickers would be different, might be different sizes, and some canvases might be completely blank if the student didn’t have the appropriate sticker.

The alternative “light-weight” lesson would just involve some paint brushes and paints. Imagine that students were able to replicate your painting perfectly. So if you paint a dog in the top corner, they will be able to paint an identical dog in the top corner of their canvas.

At the end of the lesson, then, every canvas will look more-or-less identical. At some point, you might actually tell the students to draw something different in a section that reflects their local culture. This would be fine also, and the variation would be reflected in the finished product.

This is basically the difference between a heavy-weight and a light-weight UI toolkit.

The mobile development space is getting very fragmented and form factors vary greatly. If any space needs a good platform for lightweight UI development, it is the mobile space.

Back to the Reddit Post

Responses were full of hate for Java, light-weight user interfaces, and the concept of cross-platform toolkits in general. One pervasive, yet misinformed, line of reasoning the came through in some of the frequent posters’ comments was as follows:

  1. Cross platform toolkits result in “lowest common denominator” applications that don’t take advantage of the features of any particular platform.

  2. Lightweight UIs won’t look or behave like a native on any platform so it is much better to use a heavyweight UI (i.e. wrap native components) so that the app at least looks and behaves natively.

  3. Lightweight UIs are slow! There are a million HTML5 solutions out there, but they are all laggy. It is better to just use a heavyweight UI.

  4. Cross-platform toolkits sound good at the start, but, inevitably you will hit a road block that will prevent you from achieving your goal, and have to resort to building native applications for each target platform, wasting, perhaps, a year or more of the time that you spent trying to use the cross-platform framework.

This line of reasoning appears to make sense if you don’t dig into some of the embedded assumptions. For example, #1 and #4 only hold true for heavy-weight toolkits, and #2 and #3 simply aren’t true. Let me address all of these points individually.

Do Cross-Platform Toolkits Result in a Lowest Common Denominator App?

If you develop a lightweight UI, then there is no reason why the resulting application should be the lowest common denominator of all platforms. This is because, in a lightweight UI, you are not dependent on the native widgets. You can embed native components in cases where it makes sense, but you are not limited by this. Any component in a lightweight UI can be used across all platforms, and configured to behave differently on each platform if it makes sense. Components can be created on top of a lightweight UI that don’t even exist in any of the underlying platforms. This adds a tremendous amount of flexibility and offers enormous potential.

Take, for example, the JFXtras project, which is built upon JavaFX, a light-weight UI framework for the desktop. It is a collection of components and widgets that are all light-weight (so they are truly cross platform) and they look and feel fantastic. If you wanted to develop this set of widgets using a heavyweight toolkit it would be 5 times the work, and would be impossible to maintain.

Are lightweight UIs doomed to look “un-native”?

While lightweight UIs give you the flexibility to create an app that doesn’t look native, you can come very close to a native look, if that is what you are trying to achieve. Light-weight UIs that are well designed enable you to develop themes that look and behave just like the native platform. The Swing has been doing this for years on the desktop and, while you may think that you can spot a Swing application a mile away, I am willing to bet that you have probably used many Swing applications without knowing it. Of course you can spot the ones that don’t look native – where the author didn’t place a priority on following native UI guidelines. But if you ran across one that did follow the guidelines, you would be none the wiser.

In my opinion, the Codename One folks have done a fantastic job of developing native looking themes for all of the main mobile platforms. I showed an app with the iOS theme to quite a number of savvy users and none of them could tell, at all, that it wasn’t actually using native widgets. All of the buttons look the same, and it behaved the same. This is a testament to the design acumen of their team.

And if you don’t like the look and feel, that is no problem. It is light-weight. You can override the look and behaviour of any component to conform to your preferences, if you like. Apply these changes across all platforms or only specific ones.

So, lightweight UIs certainly are not doomed to look un-native.

Are Lightweight UIs Slow?

Well, they can be, but so can heavyweight UIs. Performance depends on many factors, and if you have tried any of the HTML5 toolkits out there for building mobile apps you have probably noticed that these apps are indeed sluggish. So you might be tempted to apply the logic that since HTML5 apps are slow, and HTML5 is a lightweight UI toolkit, that all lightweight UI toolkits are slow. This is certainly incorrect. HTML5 requires very complex layout rules, and it relies on Javascript as its language that is quite a bit slower than a native executable would be. This is very hard for low-powered mobile devices to handle in a performant way. Ultimately as device performance improves (maybe in a couple years), the HTML5 performance problems will dissipate.

Codename One uses a different strategy that is much more similar to Swing than to HTML. It uses 2D drawing technology of the host platform to build its components (OpenGL on iOS, etc..) which is very fast and flexible. This allows for the creation of complex user interfaces without barely any performance hit.

So, no, lightweight UIs don’t have to be slow, and in Codename One’s case, it is not slow.

Are You Destined to Hit a Wall If You Use a Cross-Platform Framework?

I have been burned. You have probably been burned. I think everyone has been burned once or twice when they start a project with a toolkit, then sometime later, they hit a wall and the toolkit just can’t be used to take the next step. Is this inevitable with a Cross-Platform framework?

The answer is, maybe. But if you choose your framework carefully, they you shouldn’t have a problem. Some key items to look for would include:

  1. Is it open source? If it isn’t open source, then the chances are you will get stuck at some point and have to abandon it.

  2. Can you access native APIs if necessary? If you can’t access native APIs, then you will likely have to abandon it at some point.

  3. Is it built on a strong, robust, and fast foundation? If it isn’t, then you’ll likely have to abandon it at some point.

If the framework hits all three of these points, then you should be OK. If you need to access a new API on a particular platform, you can just write a native plugin for that. If you run into a bug or a limitation, you can fix it yourself, as long as it is open source. And as long as the core of the framework is strong and fast, you can build your own component libraries as time goes on to extend the platform, without worrying about breaking the platform.

Most HTML5/Javascript frameworks will fail on #3. HTML5 and Javascript just aren’t robust. There are many commercial cross-platform frameworks out there also. I would be careful with those.

In the few months that I have been working with Codename One, I have found the platform to be open and robust. If I find something that it doesn’t do, it is usually quite easy for me to add it myself. The fact that they allow you to write native plugins, wrap native components when necessary (to add to the UI), and develop my own libraries and components that run on top of it, give me confidence that there is no “wall” that I could hit in the future that would be a show-stopper.

4 Ways to Consume JSON Web Services in Codename One

I just released a Javascript bridge for Codename One that allows you to communicate easily back and forth between Java and Javascript. This library may be absorbed by the Codename One core at some point in the future, but for now it is very easy to include it with your own projects.

There are countless ways that this Javascript bridge can be used to add value to Codename One applications. In this post, I will show how it can be used as an alternate way to consume JSON web services.

Codename One already includes a JSONParser class that allows you to, quite easily, consume a web service and parse its output into a tree of Hashtables and Vectors (I will demonstrate this method below). So why use the Javascript bridge to solve an already-solved problem? The answer is: Just to prove that it can be done.

Method 1: Load data using ConnectionRequest, and parse data into Hashtables and Vectors using the JSONParser class

E.g. Loading JSON feed from Youtube for Most Popular Videos

The benefit of this method is that it is a 100% Java solution that should work the same across all platforms. It should also be very fast and efficient.

Note: Codename One offers a Result class that makes it much easier to query the result of the JSON parser. Read more about it in Eric Coolman’s blog post.

The amount of code required to consume and parse the request is not really relevant because it can all be wrapped in a single method with a callback for the result.

Method 2: Load data using WebBrowser and use Javascript’s JSON.parse() function to produce a JSObject

E.g. Loading JSON feed from Youtube for Most Popular Videos

The benefit of this method is that it is easier to obtain nested content stored in a JSObject than in a tree of Hashtables and Vectors. E.g. The same example as above (to obtain the make of a car in the result set) could be carried out on 2 lines:

JSObject response = (JSObject)context.get("JSON.parse(document.body.textContent)");
String make = response.getString("people[0].car.type.make.name");

Method 3: Pass a JSON String into JavascriptContext.get() to obtain a JSObject

E.g. Loading JSON feed from Youtube for Most Popular Videos

This is really just a hybrid of the two approaches, and it is useful if we’ve already loaded the JSON data and have it in a String. E.g. perhaps we used ConnectionRequest to load data from a Web Service, and some of the Data is JSON and some of it is another format. In any case, this method assumes that we have a String of JSON data and we want to turn it into a JSON object so that we can work with it.

Then we can pass the string directly to JavascriptContext.get(), and the WebBrowser component will handle all of the parsing.

JSObject response = (JSObject)context.get(jsonString);
String make = response.getString("people[0].car.type.make.name");

Method 4: Load data with the WebBrowser and parse it using JSONParser

E.g. Loading JSON feed from Youtube for Most Popular Videos

This is really the inverse approach of method 3 above. In this case we load JSON data in the WebBrowser, retrieve it as a string using JavascriptContext.get(), and then parse it using the JSONParser class.

AditNetwork : A Pyramid Scheme By Any Other Name …

Pyramid schemes have been around for ages. They are illegal now in Canada and the United States, but that doesn’t stop people from trying to start them up. Pyramid scheme operators have gotten crafty over the years. The “new” pyramid scheme is one that infuses a supposed product or service into the scheme so as to obfuscate its true nature as a pyramid scheme. The thing that I find frustrating is that there never seems to be a shortage of gullible victims for these schemes.

One example that I recently ran across is ADITNetwork. I uncovered this program during an investigation of strange Google Analytics results in one of the websites that I’m involved with. The website was receiving large amounts of traffic for periods of about 90 days long. Then this traffic would all disappear for a period of 90 to 180 days. This cycle occurred 3 times before I finally started to dig into the cause.

I saw that during the periods of heavy traffic I was getting a large amount of traffic (nearly all of it) from aditnetwork.com and other IP addresses that could be traced back to aditnetwork.com. But we weren’t paying them for advertising and, in fact, we weren’t doing any advertising at all so wasn’t sure exactly why they would be giving us all of this traffic.

All of the traffic was to our home page and there was 100% bounce rate.

I had to ask, what was their deal? Why would they be giving us all of this free traffic? And why was there such a high bounce rate? Something certainly wasn’t right.

The AditNetwork website is non-specific when it comes to exactly how it works. It does say:

ADITnetwork.com helps our clients establish a professional global Internet advertising platform, combined with an efficient marketing system. We can help to improve the clients website’s traffic and ranking effectively. We help the small and medium business owners not only get to be more popular and reach more potential markets, but also get more benefits through affiliate marketing. Our customers will have continuing long-term interests. We’ll form a win-win situation for all the partners and the company.

So this makes it look like they offer web-based advertising to web sites to help get them traffic. That sounds like a legitimate operation. But it still didn’t answer why they were sending us traffic, when we have never asked them to.

After a couple of Google Searches for “AditNetwork Scam” etc.., I was very surprised to find two things:

1. Google was full of pages talking about how you can get rich with Adit Network.
2. The only pages that mentioned the word “scam” seemed to be saying that it wasn’t a scam, and that it was a great business opportunity.

After reading a Facebook fan page for them, and watching a couple of Youtube videos (here and here, I now understand what their game is.

Basically they pay people to click on web advertisements. At first I thought that this was just a simple ad-clicking scam where they pay people to click on ads, then split the money earned from the click. However, that isn’t how it works. In fact, people (i.e. suckers born yesterday) *pay* AditNetwork for the privilege to be able to click on advertisements. Then, if they click on enough advertisements, they can earn up to 70% of their original investment back.

That 70% is the crux of the grand bargain. It is the remaining 30% that provides the cash pool upon which the pyramid scheme operates. Of course nobody would invest in business where the maximum they could earn was 70% of their original investment. Participants can only make a profit by signing other people up, for which they get a cut. Essentially they’re just receiving a cut of the 30% (minimum 30%) that AditNetwork will make off of their sign up fee. The following is a screenshot from their Youtube Promotional video:

Notice the break down. They pay 10% commission for people you sign up, 4% for people they sign up, down to 1% for the 9th and 10th level of sign up. And you need to be a VIP member (i.e. pay them $5000 in order to get commissions down to the 10th level). Let’s do a break-down of where the money goes if I sign up for AditNetwork. Let’s assume that commissions are paid all they way up 10 levels to an original VIP member. Then:

10% goes to the guy who signed me up
4% each goes to the next two guys up the ladder
2% each to the next 5 guys up the ladder.
1% each to the next 2 guys up the ladder.

Adding that up we get 10% + (2 x 4%) + (5 x 2%) + (2 x 1%) = 30%.

We have our magic number of 30%. So if I happen to earn back all of the remaining 70% of my investment by clicking on ads, then we see exactly where all of the money is going. Of course, if I fail to make back the full 70% or the ladder doesn’t go up that high in my case, the extra money just goes to AditNetwork. But they make money either way because they are the original VIP investor.

So we can break an AditNetwork investment down into two parts:

1. 30% of the investment goes into a pyramid scheme.
2. 70% of the investment is a deposit that you make and work off by clicking on ads.

Presumably, AditNetwork plans to be making money also by selling actual advertisements (i.e. getting websites like mine to pay them for the traffic that they generate from people clicking on ads), but an advertiser would have to be brain dead to pay for this traffic if they knew where it was coming from.

This is just another example of how easy it is to prey on people’s willingness to believe in “a free lunch”.

AditNetwork is doomed to fail because it is built on a house of cards. I’m not sure if it’s strategy is obfuscated enough to evade the laws against pyramid schemes, but it is clear that it cannot survive in the long term and many, many people will have lost their investment when the scheme dries up (like all pyramid schemes do). Advertisers would be silly to pay for advertisements on AditNetwork because the traffic they receive is false traffic (people just being paid to view their site). And the revenue stream that is being shared is coming 100% from sign-up fees. No useful work is taking place. No useful product is created. No useful service is being carried out. It is just money being funnelled in from the bottom of the pyramid to the top.

It is really sad that there seem to be so many people who allow themselves to be deceived by operations such as this one.

Develop for Mobile or Die!

If you develop software that is designed to be used by Humans, then you are now required to develop mobile-friendly user interfaces.

In 2011, a mobile user interface was a luxury. In 2012, it was a nice add-on. In 2013, it is a requirement, or your software will be headed for the junk bin. Smart phones are now ubiquitous, and tablets are taking the place of the laptop in many contexts. People are becoming savvy to what can be accomplished with a tablet, and their expectations have been significantly raised for all software that they use.

Of course, the desktop (i.e. computers with mouse or trackpad and keyboard) is not going anywhere. It is just being reserved for those heavy-duty tasks that cannot be performed with a touch device like (and this list is shrinking every year) video editing, software development, and word processing. One class of application this can now be handled wholly via a mobile interface is the CRUD application. And if it can be created for mobile, it should be created for mobile – or your users will complain (either silently by seeking out other solutions, or loudly in email).

One trend that I noticed in 2012, was a shift of user gripes originating from users using IE to users on mobile devices. At first, my canned response was: “please use a computer, not your iPad, for using this database”. Of course, the software worked on iPad, but it wasn’t optimized for the platform so it was a little painful to use. And even under the best of conditions, users will find a way to break a UI. At first, there were some valid reasons why the app had to be used on a computer. But at this point, there are no longer any technical barriers in the way of providing a mobile interface to a (mostly) CRUD application.

Transitioning CRUD Applications to Mobile

The easiest way to transition a CRUD application to mobile, is to use an HTML library like jQuery mobile. It provides a slick UI that is very similar to native. The simple act of adding a UI in jQuery mobile that is tailored specifically for mobile users will eliminate most gripes. The larger buttons and fields, combined with a more familiar mobile workflow will make your users much more at home inside your application.

Unfortunately, the similarity to native applications will invariably lead your users to start requesting features that they have seen in other native applications. E.g.:

  • We want to be able to take videos with our phone and upload them into the database. Can we do that?
  • We want to be able to use the database without being online. Can we do that?
  • We want the database to be able to track our movement and velocity and store this in the database. Can we do that?
  • The application is kind of sluggish when loading pages and scrolling, etc…. Can you improve it?

The list of feature requests is not even limited to things people have seen before … the possibilities are endless.

While HTML5 is improving all the time, and it does technically support offline apps, and limited video access, it is still very flaky, and does not approach a native experience yet. Ultimately, when your users start asking for native-like features, you need to start looking for a way to build an application that is treated as a first-class citizen on the mobile platform of choice.

Mobile Platform of Choice??? Do I really need to Choose?

The next step after outgrowing your HTML5 mobile interface (with jQuery Mobile), is to look at your options for developing a native application. I’m using “native” in a very loose sense here. Really what I mean is an application that is installed on a mobile device in the same way as the platform’s native applications. This could be an application that is written directly using the platform’s SDK or using some other toolkit that ultimately builds an application that can be installed on the device.

If you are developing a CRUD application for an organization (like I usually am), you may or may not be able to dictate that your users use a specific device. In my case, I usually can’t… or if I try it is a world of pain dealing with people that use “the other” platform. Therefore, developing separate applications for each platform is not really an option (or good use of resources). I’m still choked at having to venture outside the web-box, much less create multiple versions of the same app.
At the minimum you’ll need to develop versions for Android and iOS (but BB and WinPhone users might get on the gripe-wagon, so watch out!!).

Phone Gap

As a web developer, naturally, the first thing I looked at was Phone Gap. It allows you to develop your application using the same web tools (HTML/Javascript/CSS) and deploy it as a “native” application. The native application is essentially just a thin wrapper around a web view component. It provides some additional libraries for working with the device’s hardware like accelerometer, GPS, video camera, etc.. Because it is just a web view wrapped in an app, you can use all of the same libraries (e.g. jQuery Mobile if you like) for developing the app. If you’re lucky you won’t have to modify the existing web app at all.

Building the applications for Phone Gap can be a little more involved, as different platforms need to be set up differently, and some even differences in the application code to make it work. However, the PhoneGap build service is available to provide building in the cloud for multiple different devices. This should ease the “pain” substantially.

Phone Gap will probably give you enough flexibility to add most features you need in a CRUD application. However, you may run into issues with performance. Javascript/HTML runs much more slowly (and noticeably so on low-powered mobile devices) than native code. Facebook’s shift away from HTML5 apps to native apps last year is a key indicator that, for mobile at least, HTML5’s time has not yet come. This performance will be most noticeable when performing scrolling operations and in some transitions, but it can rear its head anywhere.

To make matters worse, on iOS, the UIWebView component doesn’t use the same Javascript engine that is used in the Safari web browser. It is substantially slower. So, by moving your application from the Web into a PhoneGap app, you will be facing a performance penalty directly from Apple.

If you are running into performance problems, or you require native features that just aren’t offered in Phone Gap, you may need to graduate to the next level: Real Native Apps

“Real” Native Apps

First, let me define what I mean when I say “Real” native apps. I mean applications that are compiled down to native executables on the supported platform. I disqualify Phone Gap from this category (and the many other HTML5 in WebView solutions) because the actual code is running inside a web sandbox.

If you have reached this level, you should at least take the various platforms’ native toolkits for a spin so that you understand how they work. Each platform offers its own unique vision for their mobile worlds. And some concepts don’t transfer easily from one platform to another. Developing for iOS is very similar to developing for Mac OS X. You use Xcode and Interface builder to develop your application logic and user interface. Generally the entire user interface is contained inside a single Nib file, and you can use the many UIController classes to control the user interface. iOS includes many useful frameworks such as CoreData which makes it easier for you to develop CRUD apps on iOS.

Android, on the other hand, is an XML jungle. The UI is defined in XML files, and so is the application configuration. It is a much more open environment than iOS, in that it is set up to encourage applications to share its components with other applications on the system.

Blackberry and Windows Phone provide their own models, but I’m not familiar with either of these platforms.

In the course of auditing the respective SDKs you’re bound to observe the elephant in the room: All of these SDKs use different programming languages. iOS uses Objective-C, Android uses Java, Windows Phone uses C# (or C++ depending on version), and Blackberry uses C++ (at least for BB10… older versions use Java).

This makes it very difficult to share code across multiple platforms. Since I don’t have the resources to maintain separate code bases for each platform, I need to either pick a single platform and run with it, or look for a solution that will allow me to develop for all of the platforms with a single code base (remember I have disqualified Phone Gap and its HTML5 ilk already if I have reached this point).

Luckily there are options:

  1. MonoTouch provides C# bindings for pretty much the entire Cocoa Touch API (iOS). It also provides bindings for Android.

  2. J2ObjC is a tool developed by google to convert Java code to Objective-C so that it can be reused for iPhone development.

  3. Oracle ADF provides a full development toolkit that allows you to build for most mobile platforms. It uses an embedded JVM for business logic, and Phone Gap for the UI…(should we disqualify this out the gate because of Phone Gap?)

  4. Appcelerator Titanium provides a cross-platform solution that provides Javascript wrappers around native components. It is different than Phone Gap in that it doesn’t run inside a web view, it merely uses the native platform’s built-in Javascript interpreter and bindings to access native components.

5. XMLVM is a low level converter that allows you to convert code between many different languages. It provides compatibility libraries for working with Android and iOS. In my opinion, this is the most ingenious software development of the past 10 years.

  1. Codename One. Codename One allows you to write mobile applications in Java and compile them into native executables for most major platforms. It uses XMLVM under the hood for its iOS port. This is, by far, the best option right now for cross-platform native mobile development, and I’ll explain why in the following section.

If you know of other options, please let me know.

These solutions can be grouped into 3 categories:

  1. Tools that assist in porting from one platform to another, but don’t provide a full development solution. These include J2ObjC and XMLVM. While these are very interesting projects, it our aim is to be able to build a cross-platform web app, then these projects won’t get us there directly. If you are developing a tool or SDK that is designed to help you and others build cross-platform apps, then these projects may be of great interest to you.

  2. Tools that allow you to share your business logic between platforms, but ultimately require a rewrite of the user interface for each platform. MonoTouch falls into this category. Really MonoTouch is a solution for C# developers who want to develop for iOS and would prefer to use C# instead of Objective-C. It isn’t really a solution for building cross-platform mobile applications.

  3. Tools that provide a full solution for developing cross-platform mobile applications. Codename One, Oracle ADF, and Appcelerator Titanium fall into this category.

Oracle ADF

I have watched videos and read documentation for Oracle ADF, but have never actually tried to build an application with it. There are a couple of show-stoppers for me on this platform:

  1. It is commercial. I wasn’t clear on the license costs, but it makes it sound like they are hoping to make large license fees off of large enterprises.

  2. They use Phone Gap for the UI. If I’m at this point (looking for a native solution and Phone Gap won’t cut it), then, ADF doesn’t meet the requirements.

Appcelerator Titanium

Appcelerator Titanium is a clever project. I spent some time last year using the desktop version to develop some desktop applications using Javascript and CSS (the desktop version actually works more like Phone Gap than their mobile version does… it embeds a web view in a native window). Ultimately I abandoned all of my desktop Titanium projects as it was apparent that the Appcelerator people were putting all of their development resources into their mobile edition and letting the desktop version languish.

The mobile edition has some promise and apparently it has their full weight behind it. The concept of using Javascript bindings for native components is interesting, although it leaves open some of the same performance problems that plague PhoneGap. From what I have read in various forums and blogs, Appcelerator mobile apps do run into performance and memory problems if they are not developed carefully. Although they seem to be getting better with each release.

Appcelerator provides an API that generalizes commonalities between different platforms, but it enables you to write plugins that are platform specific if you need to use features of a platform that aren’t available in the API. This blog (presumably by someone who knows titanium – “titaniumninja”), argues that Appcelerator isn’t really a “Write Once Run Anywhere” tool:

Titanium isn’t a write-once-run-everywhere platform. As Appcelerator’s guys use to say, its aim is to be a write-once-adapt-everywhere tool, since, while using a common high level language and API, it enables the exploitment of platform specific features when needed. This philosophy is clearly visible in the API, as we have entire sub-namespaces dedicated to either iOS, or Android. This allows adapting our mobile applications to the platforms where they’re executed, thus avoiding a write once, suck everywhere effect. Moreover, the possibility to develop custom native extensions to the framework opens up a wide range of development scenarios, ideally allowing us to create user experiences that are practically undistinguishable from those of applications developed with native SDKs.

This description/warning seems realistic and makes me optimistic about the platform. If you are a Javascript/CSS ninja, then Appcelerator will probably provide an accelerated path to a mobile application, while not inhibiting you with a glass ceiling. I really like to be able to build native plugins for high-level frameworks. Otherwise I feel like I’m one feature request away from having to abandon the platform.

Without having dug too deeply into Appcelerator’s API, there are a couple of negatives (when compared with Codename One or native app development) that appear right off the bat:

  1. Javascript is a bitch to debug compared with managed languages like Java and C#.
  2. Memory management and performance are likely issues, and you may need to dig into the “native plugins” crutch sooner than later to resolve such issues.

If Appcelerator was the only cross-platform solution on the market, you can bet I’d be using it.

But Codename One exists…

Codename One

I have been developing with Codename One for a couple of months now. Based on that, you would probably guess that it was my choice for developing native mobile apps. You would be correct. When you line up all of the other options for development (native SDKs, Appcelerator, ADF, etc..), Codename One wins on almost every front.

What do I like about Codename One?

Codename One is the only true write-once-run anywhere solution out there (for native apps). It uses OpenGL (I believe on all platforms, but any graphics toolkit could be used if something better came along) as the foundation upon which its rich set of components are built. This makes it much easier to port to different platforms than, say Appcelerator, because all of the widgets are light weight (Similar to Swing in the Java Desktop world). The user interface can be styled using themes to look exactly like the native platform, and they provide native themes for all platforms for which they produce apps.

Applications are written in Java and they are compiled into native binaries (on iOS they use XMLVM to produce native C code that is compiled into an ARM binary using LLVM). They provide plugins for Netbeans and Eclipse, as well as a simulator to be able to run and preview your apps right in the IDE. The resource editor application also provides rich GUI development tools for forms and themes.

Basically, they have provided for the entire development cycle. They don’t leave you hanging. They even provide a cloud build server for you to build your applications without having to install the native SDKs. This allows Windows users to build iOS apps, and Mac users to build Windows Phone apps. (Initially I was concerned that I wouldn’t be able to do my own builds offline, but this was unfounded, as I was able to, without too much difficulty, set up my own build environments for iOS and Android… and I have no reason to believe it will be any more difficult for Blackberry).

The performance of CodenameOne apps is near native, and may even be faster than native apps in some case (e.g. Java method calls are 3 to 4 times faster than Objective-C message calls).

All of these features (the GUI builder, simulator, build server, Netbeans plugins, etc..) was enough to make me try it. But I stayed for the API. CodenameOne’s API is a joy to use. Their founders have a real knack for building clean UIs that are easy for developers to figure out. It appears to be heavily influenced by Swing, but with all of its demons exorcised. As an experiment I set out to write an application using the Android SDK, the iOS native SDK, and Codename One separately to get a feel for the differences in the API. By far, the Codename One API provided the most fluent experience.

In places where the API doesn’t support something, Codename One provides native interfaces that allow you to develop your own native libraries that interoperate with Codename One. This means there is no glass ceiling. Anything you can do on a native platform, you can do on Codename One.

If you are a Java developer, you really should be using Codename One to develop your mobile apps. Otherwise you are wasting precious resources and excluding potential users and platforms from enjoying your application.

If you are not a Java developer, and you want to develop mobile apps, I still think that you would be better off learning Java and jumping on the Codename One wagon than spend your time developing for another platform.

Ramblings about Xataface, Java, and other software development issues