To develop editors with the Experience Manager Editor SDK, you must have the following components:
Flex SDK 4.5.x or Flash Builder — Flash Builder is an integrated editing and debugging environment offered by Adobe. It requires a developer license. The raw SDK is open source and also available from Adobe. You can consult the wiki at http://sourceforge.net/adobe/flexsdk/wiki/About/ for additional information.
Additionally, Oracle recommends using Apache Maven 3.0.4 to build your projects. Apache Maven is an open source project hosted at http://maven.apache.org/.
Flex is an open source development framework created and maintained by Adobe. It supports common design patterns and is based on MXML and ActionScript 3. If you are unfamiliar with Flex, you may find the following resources helpful:
http://www.adobe.com/products/flex.html — The Adobe Flex Web site provides an overview of the Flex development framework and includes download links to the Flex SDK.
http://help.adobe.com/en_US/Flex/4.0/UsingSDK/index.html — The Adobe Flex 4 resources page contains links to Flex documentation, including the ActionScript 3.0 Reference and ActionScript 3.0 Developer's Guide.