Flash Builder 4.5 supports installing it as a plug-in into an existing Eclipse instance. The specific operation is as follows: Complete the above installation process. Navigate to the installation location of the Flash Builder and open X:/fb4.5/adobe Flash Builder 4.5/utilities. Run the executable file Adobe Flash Builder 4.5 Plug-in Utility.exe. Select the language and click OK. Follow the prompts to select the Flash Builder installation location. Select the Eclipse folder where you want to insert Flash Builder 4.5, and then click Next. (Note: The Eclipse version must be 3.6.1 or later (32-bit) and must contain a folder named "Dropins"). Review the preinstallation summary, and then click Install. During the installation process, it is recommended that you edit the Eclipse.ini file for the Eclipse instance to include the following settings:
-vmargs-xms256m-xmx512m-xx:maxpermsize=256m-xx:permsize=64m
Original address: http://kb2.adobe.com/cn/releasenotes/890/cpsid_89021.html