Flex development tools


Configuration files

You must be familiar with the ways to configure your development environment. Adobe Flex Software Development Kit (SDK) primarily provide XML files that you use to configure the settings. The flex-config.xml file defines the default compiler options for the compilers.

In addition to server and compiler configuration settings, you can also modify the messaging and data management settings, the JVM heap size, Adobe® Flash® Player settings, and logging and caching settings.

For more information about configuring your Flex SDK environment, see SDK configuration.


Flex includes application compilers and component compilers. You use the application compilers to compile SWF files from MXML and other source files. You use the component compilers to compile SWC files from component files. You can then use SWC files as dynamic or static libraries with your Flex applications.

The application compilers take the following forms:

  • Adobe® Flash™ Builder™ project compiler. The Flash Builder application compiler is opened by Flash Builder for Flex Projects and ActionScript Projects.

  • mxmlc command-line compiler. You launch the mxlmc compiler from the command line to create a SWF file that you then deploy to a website.

  • fcsh compiler shell. Provides an optimized environment for using the mxmlc command-line compiler. For more information, see Using fcsh, the Flex compiler shell.

The component compilers take the following forms:

  • Flash Builder library project compiler. The Flash Builder component compiler is opened by Flash Builder for Flex library projects.

  • compc command-line compiler. You open the compc compiler from the command line to create SWC files. You can use these SWC files as static component libraries, themes, or runtime shared libraries (RSLs).

For information on using the compilers, see Flex compilers.


To test your applications, you run the application SWF files in a web browser or the stand-alone Flash Player. If you encounter errors in your applications, you can use the debugging tools to set and manage breakpoints in your code; control application execution by suspending, resuming, and terminating the application; step into and over the code statements; select critical variables to watch; evaluate watch expressions while the application is running; and so on.

Flex provides the following debugging tools:

Flash Builder debugger 
The Flash Builder Debugging perspective provides all of the debugging tools you expect from a robust, full-featured development tool. You can set and manage breakpoints; control application execution by suspending, resuming, and terminating the application; step into and over the code; watch variables; evaluate expressions; and so on. For more information, see Debugging, testing, and monitoring applications.
The fdb command-line debugger
The fdb command-line debugger provides a command-line interface to the debugging experience. With fdb, you can step into code, add breakpoints, check variables, and perform many of the same tasks you can with the Flash Builder visual debugger. For more information, see Command-line debugger.
AIR Debug Launcher (ADL)
ADL is a command line debugger for Adobe® AIR™ applications that you can use outside of Flash Builder.


You can log messages at several different points in a Flex application’s life cycle. You can log messages when you compile the application, when you deploy it to a web application server, or when a client runs it. You can log messages on the server or on the client. These messages are useful for informational, diagnostic, and debugging activities.

Flex includes the following logging mechanisms that you use when working with Flex applications.

Client-side logging
When you use the debugger version of Flash Player or start your AIR application using AIR Debug Launcher, you can use the trace() global method to write out messages or configure a TraceTarget to customize log levels of applications for data services-based applications. For more information, see Client-side logging and debugging.
Compiler logging
When compiling your Flex applications from the command line and in Flash Builder, you can view deprecation and warning messages, and sources of fatal errors. For more information, see Compiler logging.