I have a eclipse plugin project (LSclipse), and two java projects (I’ll call them A, B) that LSclipse uses.
Two projects are Linked Folder in LSclipse, and everything works fine in eclipse IDE.

When I tried to export the project as eclipse plug in, I got an error.

The error messages are caused by those types in the A, B projects are not properly referenced.
2. ERROR in /Users/smcho/Dropbox/smcho/workspace/seal2/LSclipse/src/lsclipse/LSDiffRunner.java (at line 61)
import edu.washington.cs.induction.OnePipeLineScript;
^^^
The import edu cannot be resolved
I unzip the partially generated jar file and found that all the class files in A, B are compiled correctly.
The Package Explorer shows the packages in A, B without any issue other than blank folders.

I added A, B in the build.property,

and now I have this error saying those directories do not exist beneath LSclipse directory.

What’s wrong with this?
I don’t know why Linked Foler works, but I could use symbolic link to get the working exported plugins.
I also think exporting jars for the dependent projects first, and then include them as library can be another way to solve this issue.
Reference – Errors in exporting eclipse deployable plug-ins and fragments