Adobe is planning to open source Flex, a development framesork for building Flash and Apollo based applications. Adobe is expecting the open source community will contribute to evolutions of Flex framework. The Flex source code is expected to release under MPL (Mozilla Public License).

Flex is used for building Rich Internet Applications, using framework developers can create application that runs on Flash Player or Apollo (Adobe desktop media player). Flex Framework source code is already available with the free distribution of Flex SDK, by the end of the year Adobe is expecting to complete the transtion to a fully open source project.

What components are being released to open source?

Adobe plans to release all of the components of the Flex SDK needed to create Flex applications, including the Java source code for the ActionScript and MXML compilers, the ActionScript debugger, and the ActionScript libraries that make up the core Flex framework. Adobe Flex Builder, the Eclipse-based IDE, is not part of the open source announcement.

Adobe announcement is here