Top 10 Adobe Flex Misconceptions

| by Jon Rose Follow 0 Followers on Dec 10, 2007. Estimated reading time: 8 minutes |
At QCon, Adobe's James Ward shared with the top Adobe Flex misconceptions that he encounters in his travels evangelizing the Flex application framework.
  1. Users Need to Install Something New to Run Flex Applications.

    Ward, exclusive to, discusses the Flash adoption rates and Flex programming model:
    Flash Player 9 is required for Flex 2 & Flex 3. The Flash Player 9 runtime is currently installed on 94% of the world's computers:

    Flex 2 and Flex 3 applications execute in the Flash Player 9. Flex applications are built on top of the native Flash Player APIs like vector graphics, bitmap manipulation, and networking (which are based on the browser networking stack). The Flex framework adds reusable components like date pickers, data grids, charts, etc. Compiling a Flex application results in a SWF file which is the binary byte code format for the Flash Player. Contained in the SWF file is the byte code for the Flex framework code and a project's custom code. The Flex compiler optimizes the byte code so that only classes which are used go into the SWF file.

    For desktop applications, Adobe is aiming to make their new desktop runtime, dubbed Adobe AIR, as ubiquitous as the web runtime. The 1.0 release of Adobe AIR will be available in the beginning of 2008. Currently, AIR is in beta release from Many companies are already building production applications on AIR. One example, can be seen with eBay's application eBay Desktop.
  2. Flash Player is 100% Proprietary.

    Ward continued on this item for
    The core of Flash Player is the Tamarin Virtual Machine, which is an open source project under Mozilla. While the SWF file format is not fully open, it is documented by the community on There are numerous open source products that read and write SWF files. The Flash Player's product direction has traditionally been heavily influenced by the community and their needs. The core language for Flash Player is an implementation of ECMAScript 262, which is the specification for JavaScript. Flex also uses CSS for styling of components / applications. Adobe AIR uses web standards as the basis for desktop applications as well as Open Source technologies like Tamarin, Webkit, and SQLite.
  3. Flash is for Designers, Video, and Annoyances.

    In Ward’s July, 2007 blog, “How I Overcame My Fear of Flash,” he discussed this point:
    Indisputably, the power of Flash has been abused. Pop-ups, pop-overs, skip intros and annoying ads run rampant across our screens. I've heard it said that one should never judge a religion by its abuse. The same adage applies to technology. Flash shouldn't be avoided just because people use it for annoying things. After all, e-mail isn't avoided just because spammers happen to abuse it.
    Ward elaborated on the topic for
    Traditionally Flash content was built with the timeline based tool for designers. Flex is the developer toolset for building Flash based content / applications. Designers and developers can work together by sharing assets between the two tools. Flex adds a comprehensive component base:
  4. Flex is Not for Enterprise / Business Applications.

    Over the last few weeks, Ward published a seven part blog series on a number of new Oracle applications implemented in Adobe Flex. The applications, which were announced at the recent Oracle OpenWorld, ranged from sales tools, to database management, and business intelligence.

    In addition to Oracle’s usage of Flex, published a piece recapping a number of groups using Flex for enterprise applications. Ward also points out to, that there are numerous examples of enterprise applications being developed with Adobe Flex, including work at: Workday, SAP, Salesforce, and Business Objects.

  5. Flex is Expensive.

    Ward detailed a number of things Adobe has done to address the cost concerns:
    Flex is a free, and soon to be open sourced, developer toolkit for building Rich Internet Applications for the web and the desktop. This free SDK includes everything a developer needs to build RIAs that work the same on any browser or operating system. Part of the free Flex SDK is an extensive set of components which are extensible, skinable, and accessible. You can see many of these components in the Flex Component Explorer:

    Flex Builder is an optional plugin for Eclipse which makes developing applications with the free Flex SDK more efficient. It includes features like integrated debugging, design view, and code completion.

    The Flex Builder pricing has changed in quite a few ways recently. Flex Builder is now free for Students and Faculty. The price for the vanilla Flex Builder, without the charting components, has been reduced to $249 to better balance the tiered pricing for Flex Builder.

    There are a number of options for building backend infrastructure for Flex Applications. To take advantage of the high performance AMF data transfer protocol, there are official Adobe products like LiveCycle Data Services, as well as numerous open source projects like Granite Data Services. Using AMF removes the unnecessary steps of converting data to text (SOAP, RESTful, etc), transferring it, and then converting it back to data. AMF also allows type information to be preserved across the wire.
    To see a comparison of AMF to other text based serialization technologies, see James Ward's Census RIA Benchmark application:

  6. Flex Applications Require a Special Server.

    Once again, Ward speaking with
    Flex applications can run on top of any web server, application server, and database server. Flex applications are much more like client-server applications. Since the logic is running on the client inside the Flash Player, you need some way of communicating with the server. There are many different options for how you connect Flex to your infrastructure. Without any special libraries, you can expose your back-end data and services as RESTful, XML, or SOAP and easily consume that data in your Flex application. If you choose to use the AMF binary serialization protocol, you may need to add some additional libraries into your web application. AMF is just another serialization technology, like XML or JSON, so it can be one of the various methods you use to communicate to your back-end SOA.
  7. Flex is Hard to Learn.

    Leftie Friele, from the community, posted a comment on the piece “Who is Using Flex?”, detailing his company’s experience in learning Flex:
    Our startup company, Ezmo, have used Flex since the start and we're extremely happy with the framework.

    Without any prior knowledge of Flex/Flash, we built our application in less than two weeks. The integration between Java and Flex is super simple, and getting started with Flex is just a walk in the park.

    The tool support is very good too with Flex Builder. You get the familiar surroundings of Eclipse and you are off and running without many problems. The one thing that is missing is better tools for continuous integration and better plugins into Maven for building Flex applications.
    For those new to Flex, Ward has a Screencast showing a Flex application being built to help get you started. There are also numerous other articles about using Flex and Java in the Adobe Developer Connection.

  8. With Flex, I Will Need to Rebuild My Entire Application.

    In January, Bruce Eckel published an article titled, “Hybridizing Java.” He argues that the Java community should continue using the good parts of Java, but should use other technologies where Java is weak. His primary focus in the article is using Adobe Flex for user interfaces, instead of the traditional Java options (Swing, JSF, etc…).

    Ward elaborates on this concept:
    Since Flex applications are just the UI piece of an application the back-end usually stays the same. If your back-end was built following the SOA pattern then it is usually very easy to expose those services out to a new Flex UI. This preserves your existing business logic whether it is in EJBs, Spring services, POJOs, etc.
  9. Flex Breaks Normal Browser Functionality, Like the Back Button.

    Ward’s blog discusses the back button:
    In Flex, back button support is built in and easily customizable so this was never an issue. Flex also provides an easy way to do hashmark urls (or named anchors), so the url changes as application state changes. Another Web 1.0 integration problem solved.
    Ward adds more details for
    Flex 3 provides a simple way for applications to store state parameters in a named anchor and correctly restore state based on those parameters when the URL is requested. More information about this feature can be found in the Flex 3 Feature Introductions Deep Linking documentation.

    Accessibility has always been very important for Flex applications. Since the Flash Player works with Jaws and other accessibility technologies, the capability for adding accessibility to Flash based applications is there. The Flex framework builds accessibility into the core framework. There are many different pieces of accessibility depending on what impairments and disabilities your application needs to support. You can find out more about the accessibility features of Flex in the Developer's Guide.
  10. I Can Do Everything Flex Does With Ajax.

    Ward explains:
    RIA with Flex and Ajax is not either/or. Sites like Google Finance show how you can use Flex and Ajax together. Ajax is very good for content-centric applications, while Flex is very good for interactive, media, and data-centric applications. If your application is somewhere in between the two sides of that spectrum, then you can use the Flex Ajax Bridge to combine the two technologies. In Flex 3, the Flex Ajax Bridge is integrated directly into the SDK. If you are using Flex 2, you will need to download the Flex Ajax Bridge separately.
    Also, from the community, Michael Marth commented on why his group chose Flex:
    We use Flex 2 for our soon-to-launch online dating site

    The reason: Flex enabled us to create a user experience far beyond anything that we could have done with a comparable effort in Javascript/Ajax.
For those of you in the community, are these misconceptions you have held about the Adobe Flex framework? Are there additional barriers that Adobe has yet to address, which are keeping you from using the Flex application framework?

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LET THE FLAMES BURN!!!! by Janos Haber

Adobe doesn't care about fixing critical issues in current commercials versions of the software, rather fixes them in the next version, therefore forcing an update.

Re: LET THE FLAMES BURN!!!! by James Ward

Hi Janos,

All commercial software has bugs. It's always hard for vendors to decide what gets fixed and what gets deferred. I'm sorry that your particular bug was deferred. But you do have the source code for the charting components. So if this a critical issue for you which you cannot wait for Adobe to fix then you can fix it yourself. This particular issue doesn't seem like it would be too difficult to fix.


Media Server by Michael Neale

I have had some success with Red5 - seems to work well with RTMP from flash "clients".

Re: LET THE FLAMES BURN!!!! by James Ward


Check out the bug again. It has been updated by the engineering team. Turns out not to be a bug. They have also provided you with information on how to do what you need. Let us know if that information doesn't solve your problem.


Item #8 by Jacob Hookom

James, I think you've mentioned this in other posts, but I think simply stating that you're just changing the UI is a bit of a misconception. When you are doing server-side rendering of data, you don't need to think about SOA-- or if you have SOA, the contracts may be meant for internal consumption and not public.

While I love Flex and the future that AIR holds, it does force you to take a different perspective on data-- you can't simply "output it" from local Java memory-- you have to think about networking, RPC, security, etc. You basically end up with an extra step in the development process, and depending on your data, this can be easy or quite difficult in the context of marshalling state behavior behavior vs. what's contained on the server.

Is that Flex's fault? No way. I just think the Java platform needs something better for querying/filtering datasets back to external clients. I think the tipping point here is if you can contain the users' complete data domain within the client. If so, Flex is cake-- if not, you're going to have to develop a bit of SOA layers/contracts to make sure things stay efficiently usable without a lot of development overhead.

Re: Item #8 by Jon Rose

I would agree that Flex does introduce some new concerns with back-end integration. Although, it maybe better said that it introduce different considerations, as it simplifies a number of things. Generally, I have found that when building Flex based applications I am able to heavily leverage my existing Java skills, and most all of my new learning has been focused on the UI / Flex framework side.

Re: Item #8 by James Ward

Hi Jacob,

Thanks for the clarification. You are totally correct. Usually when there is only a web interface the service layer exists primarily to support the web interface which heavily uses server-side state. Applications which only have a traditional web interface many need to rebuild their services layer if their services were designed only for this method of interaction. However applications which already have a stateless services layer typically do not need much additional work.


Re: Item #8 by Michael Neale

I don't think flex is different from ajax in that regard (in terms of a 100% ajax interface like say gmail).

ActionScript 3 is not to shabby either. The online docs are nice, with pretty helpful examples (I only have experience with the flex compiler building more "normal" flash things, not so much calling remote services).

If flash was opened up all the way into open source, I would be one happy camper. Gnash is coming along in the meantime.

Flash Penetration by Gary Ault

How does 93.3% of Mature markets and 89.4% of Emerging markets on internet-connected, non-corporate, non-government PC's translate to "94% of all computers in the world."

accessibility has traditionally been an issue by Knut Forkalsrud

things like being able to use the arrow keys on the keyboard (not to mention page-up/page-down) has been a disappointment in most flash UIs to date.

Right-to-Left languages by Alex Bental

Flex is a very good UI framework, I played with it a little bit and all my Java knowledge was useful while catching up with it.
I thought of Flex as a potential UI framework for one of my projects, but it turned out that Flex (it's a Flash problem mainly) has no good support for right-to-left languages. Adobe doesn't seem really wishing to fix the problem. I have these problems in my tests of Flex 2.
Is Adobe planning to fix the issue and make the RTL support built-in?

Re: Right-to-Left languages by James Ward

Hi Alex,

Flash 10 will have RTL support.


Re: Flash Penetration by James Ward

The 89.4% number was from June 2007. The 93.3% number was from September 2007. Following the historical trends Flash 9 is beyond 94% adoption worldwide today.


Re: Flash Penetration by Gary Ault

But do these numbers measure flash penetration in corporate and government environments?

Re: Flash Penetration by Jon Rose

Assuming one was to take Adobe’s numbers at face value, how do these numbers compare to other client side runtimes? I can’t seem to find any numbers on JVM installs.

Re: Flash Penetration by Bobby Lewis

Are there any major e-commerce applications which have implemented their forms/functionality with Flex? Requiring your customers to have the plugin and tolerate the larger downloads when you are a major revenue channel for your company is a big pill to swallow.

Re: Flash Penetration by James Ward

Hi Bobby,

I've seen a few e-commerce applications using Flex:


Re: Flash Penetration by James Ward

Hi Gary,

The penetration study is a general audience. So it covers home, corporate, and government users. While most people I talk to in corporate environments find that their user base is within a few percent (either way) of our published numbers, I always encourage people to test their user base. Maybe they all have green screens and thus no Flash. Let us know what you find.


Re: Flash Penetration by James Ward

The only numbers I've seen are from Joshua Marinacci of Sun. He says that "77% of all PCs have a Sun JVM installed". This was posted to the Java Posse Google Group:


Re: Flash Penetration by James Ward

One more Flex e-commerce site I just found:

Thanks by Steve Fuller

I have been keeping an eye on Flex for some time now. I just wanted to say I appreciate the opinions of everyone regarding this article. Having never used it, I can't comment, but I have seen some amazing implementations of it and it does look promising. This article does a pretty good job of addressing some key questions that I've been milling over. Anyone know of any glaring deficiencies not mentioned here? Or better yet, places where Flex excels in doing particular tasks?

Flex + RAD = Snapp MX by Harald Kobler

Flex is a great tool for "Designer" applications but some people are just looking for a way to develop data-centric applications rapidly while leveraging the benefits of Flash. This is where Snapp MX comes into play (see If you're interested a comparison between the two products can be viewed at:

Load testing Flex applications by Ethan Jones

There is a really good whitepaper about the need to load test Flex applications. It can be accessed here:

Re: accessibility has traditionally been an issue by hank jmatt

Hello, Knut Forkalsrud.
Are there any major e-commerce applications which have implemented their forms functionality with Flex? Requiring your customers to have the plugin and tolerate the larger downloads when you are a major revenue channel for your company is a big pill tower defense to swallow.

Thanks by Oyun Cambazı

The only numbers I've seen are from Joshua Marinacci of Sun.Oyun

Re: accessibility has traditionally been an issue by Aren Fishman

Great post NRG. From reading different forums and posts a lot of people have a misconception about Flex. This post does a great job in explaining a little bit about Flex and how its not a scary monster.
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