Originally posted by Ed Burnette:
Don't give up yet! I believe all you need to do is:
1. Create a new project called, just for example, root1.a (File > New > Java > Java Project).
2. Right click the project and select New > Folder.
3. Call the new folder root1. Don't press Finish yet.
4. Select Advanced, turn on the Link to folder in the file system option, and type or browse to the location of the real root1 folder. Now press Finish.
5. Right click the project, select Properties > Java Build Path > Source. Expand the source folder and double click the Exclusion filter.
6. Select Add Multiple. Expand root1 and select all its immediate children except for a. (on Windows you do this by clicking on the first one, shift-clicking on the last one, and control-clicking on any in the middle to toggle). Then press OK a few times to get out of all the dialogs.
The linking feature is similar to NetBeans' virtual filesystem but should be familiar to Unix users used to symbolic links. And no matter how many directories you need to exclude it's only one step to exclude them all at once.